feat(metadata): implement single-track metadata editor page (§A7)

Replace the placeholder with a controlled form for title/artist/album/
year/genre/track number, an AcoustID "find matches" action showing
ranked candidates with confidence, a diff/apply picker, a re-enrich
button, and save via PUT /metadata. Adds matches/apply API endpoints,
mappers, types, and en/ru i18n strings. Batch editor remains a
placeholder (deferred).

.env.example

@@ -1,2 +1,6 @@
 # Default backend URL (overridable at runtime in the UI)
 PUBLIC_API_BASE_URL=http://localhost:8080/api/v1
+
+# Show the public sign-up UI on the connect screen. Set to false to hide it.
+# The backend's ALLOW_REGISTRATION is the real authority; this only gates the UI.
+PUBLIC_ENABLE_REGISTRATION=true

.gitea/workflows/docker-publish.yml

@@ -0,0 +1,121 @@
+name: Docker Build & Publish
+
+on:
+  push:
+    branches: [master]
+  workflow_dispatch:
+
+env:
+  # Number of tagged (non-latest) versions to keep per image name.
+  KEEP_VERSIONS: "5"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    outputs:
+      host:  ${{ steps.meta.outputs.host }}
+      image: ${{ steps.meta.outputs.image }}
+      sha:   ${{ steps.meta.outputs.sha }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Resolve registry metadata
+        id: meta
+        run: |
+          host=$(echo "${{ gitea.server_url }}" | sed 's|https\?://||; s|/$||')
+          repo_lc=$(echo "${{ gitea.repository }}" | tr '[:upper:]' '[:lower:]')
+          echo "host=$host"            >> "$GITHUB_OUTPUT"
+          echo "image=$host/$repo_lc" >> "$GITHUB_OUTPUT"
+          echo "sha=$(git rev-parse --short HEAD)" >> "$GITHUB_OUTPUT"
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Build image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          file: dockerfiles/Dockerfile.prod
+          push: false
+          build-args: |
+            PUBLIC_API_BASE_URL=/api/v1
+          tags: |
+            ${{ steps.meta.outputs.image }}:latest
+            ${{ steps.meta.outputs.image }}:${{ steps.meta.outputs.sha }}
+          outputs: type=docker,dest=/tmp/image.tar
+
+      - name: Upload image artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: docker-image
+          path: /tmp/image.tar
+          retention-days: 1
+
+  push:
+    needs: build
+    runs-on: ubuntu-latest
+    steps:
+      - name: Download image artifact
+        uses: actions/download-artifact@v3
+        with:
+          name: docker-image
+          path: /tmp
+
+      - name: Load image
+        run: docker load < /tmp/image.tar
+
+      - name: Log in to Gitea registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ needs.build.outputs.host }}
+          username: ${{ gitea.actor }}
+          password: ${{ secrets.PACKAGE_REGISTRY_TOKEN }}
+
+      - name: Push image
+        run: |
+          docker push ${{ needs.build.outputs.image }}:latest
+          docker push ${{ needs.build.outputs.image }}:${{ needs.build.outputs.sha }}
+
+  cleanup:
+    name: Prune old image versions
+    needs: push
+    runs-on: ubuntu-latest
+    steps:
+      - name: Delete versions beyond KEEP_VERSIONS
+        env:
+          GITEA_URL: ${{ gitea.server_url }}
+          OWNER: ${{ gitea.repository_owner }}
+          IMAGE: ${{ gitea.event.repository.name }}
+          TOKEN: ${{ secrets.PACKAGE_REGISTRY_TOKEN }}
+        run: |
+          image=$(echo "$IMAGE" | tr '[:upper:]' '[:lower:]')
+
+          # List all container package versions for this image (page size 50 is
+          # enough for typical repos; increase if you push very frequently).
+          response=$(curl -sf \
+            -H "Authorization: token $TOKEN" \
+            -H "Accept: application/json" \
+            "${GITEA_URL}/api/v1/packages/${OWNER}?type=container&limit=50&q=${image}")
+
+          # Keep the KEEP_VERSIONS newest SHA-tagged versions; always preserve 'latest'.
+          to_delete=$(printf '%s' "$response" \
+            | jq -r \
+                --arg  name "$image" \
+                --argjson keep "$KEEP_VERSIONS" \
+                '[.[] | select(.name == $name and .version != "latest")]
+                 | sort_by(.created) | reverse
+                 | .[$keep:][].version')
+
+          if [ -z "$to_delete" ]; then
+            echo "Nothing to prune."
+            exit 0
+          fi
+
+          while IFS= read -r version; do
+            echo "Deleting ${image}:${version}"
+            curl -sf -X DELETE \
+              -H "Authorization: token $TOKEN" \
+              "${GITEA_URL}/api/v1/packages/${OWNER}/container/${image}/${version}" \
+            && echo "  ok" || echo "  failed (may already be gone, continuing)"
+          done <<< "$to_delete"

dockerfiles/30-runtime-config.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+# Write the SPA's runtime operator config at container start.
+#
+# The nginx base image runs every /docker-entrypoint.d/*.sh before launching
+# nginx, so this overwrites the build-time public/config.js stub with the
+# operator's runtime config ($PUBLIC_API_BASE_URL, $PUBLIC_ENABLE_REGISTRATION).
+# That lets one prebuilt image target any backend origin and toggle sign-up
+# without rebuilding. Resolution + precedence live in src/config/env.ts.
+set -eu
+
+: "${PUBLIC_API_BASE_URL:=/api/v1}"
+: "${PUBLIC_ENABLE_REGISTRATION:=true}"
+ROOT="${NGINX_HTML_ROOT:-/usr/share/nginx/html}"
+
+# Anything but "false"/"0" enables the sign-up UI (mirrors parseFlag in env.ts).
+if [ "$PUBLIC_ENABLE_REGISTRATION" = "false" ] || [ "$PUBLIC_ENABLE_REGISTRATION" = "0" ]; then
+  ENABLE_REGISTRATION=false
+else
+  ENABLE_REGISTRATION=true
+fi
+
+printf 'window.__APP_CONFIG__={"apiBaseUrl":"%s","enableRegistration":%s};\n' \
+  "$PUBLIC_API_BASE_URL" "$ENABLE_REGISTRATION" \
+  >"$ROOT/config.js"
+
+echo "runtime-config: wrote apiBaseUrl=$PUBLIC_API_BASE_URL enableRegistration=$ENABLE_REGISTRATION to $ROOT/config.js"

dockerfiles/Dockerfile.dev

@@ -4,14 +4,9 @@
 # shadows the container install. Build context = mcma-webui/.
 FROM node:22-slim
 
-# `modern-sk` is a git dependency (git+https://...) — npm needs git to fetch it.
-RUN apt-get update \
-    && apt-get install -y --no-install-recommends git \
-    && rm -rf /var/lib/apt/lists/*
-
 WORKDIR /app
 
-COPY package.json package-lock.json modern-sk-*.tgz ./
+COPY package.json package-lock.json ./
 RUN npm ci
 
 COPY . .

dockerfiles/Dockerfile.prod

@@ -8,13 +8,14 @@ FROM node:22-slim AS build
 
 WORKDIR /app
 
-COPY package.json package-lock.json modern-sk-*.tgz ./
+COPY package.json package-lock.json ./
 RUN npm ci
 
 COPY . .
 
-# Bake the API base URL at build time (rsbuild inlines PUBLIC_* vars).
+# Build-time default for the API base URL (rsbuild inlines PUBLIC_* vars). This
-# Same-origin default ('/api/v1') works behind any reverse proxy.
+# is only the *fallback* now — the real value is injected at container start by
+# 30-runtime-config.sh, so the image can target any backend without a rebuild.
 ARG PUBLIC_API_BASE_URL=/api/v1
 ENV PUBLIC_API_BASE_URL=$PUBLIC_API_BASE_URL
 RUN npm run build
@@ -25,5 +26,10 @@ FROM nginx:1.27-alpine AS runtime
 COPY dockerfiles/nginx.conf /etc/nginx/conf.d/default.conf
 COPY --from=build /app/dist /usr/share/nginx/html
 
+# Runtime config injection: the nginx image runs /docker-entrypoint.d/*.sh
+# before starting, regenerating /config.js from $PUBLIC_API_BASE_URL.
+COPY dockerfiles/30-runtime-config.sh /docker-entrypoint.d/30-runtime-config.sh
+RUN chmod +x /docker-entrypoint.d/30-runtime-config.sh
+
 EXPOSE 80
 CMD ["nginx", "-g", "daemon off;"]

dockerfiles/nginx.conf

@@ -14,6 +14,13 @@ server {
         try_files $uri =404;
     }
 
+    # Runtime operator config — regenerated per container start, so it must
+    # never be cached or a redeployed backend URL would be ignored.
+    location = /config.js {
+        add_header Cache-Control "no-store";
+        try_files $uri =404;
+    }
+
     # SPA: every unknown path falls back to index.html (client-side router).
     location / {
         try_files $uri $uri/ /index.html;

package-lock.json

@@ -8,7 +8,7 @@
       "name": "mcma-webui",
       "version": "1.0.0",
       "dependencies": {
-        "@olly/modern-sk": "0.1.4-3",
+        "@olly/modern-sk": "^0.1.5",
         "@phosphor-icons/react": "^2.1.10",
         "@reduxjs/toolkit": "^2.12.0",
         "i18next": "^26.3.1",
@@ -693,9 +693,9 @@
       }
     },
     "node_modules/@olly/modern-sk": {
-      "version": "0.1.4-3",
+      "version": "0.1.5",
-      "resolved": "https://git.ollyhearn.ru/api/packages/olly/npm/%40olly%2Fmodern-sk/-/0.1.4-3/modern-sk-0.1.4-3.tgz",
+      "resolved": "https://git.ollyhearn.ru/api/packages/olly/npm/%40olly%2Fmodern-sk/-/0.1.5/modern-sk-0.1.5.tgz",
-      "integrity": "sha512-h+d+Jd3DBr7d51V78p1Eb5rVrpN4PAskwQFnh2X4Dk7Q8oajiMVJuhZU1amx97bKHFDHgcOfhwc4cS8P4tFCmQ==",
+      "integrity": "sha512-rhKp4U2IovSZkgdfg4oZqyhF0GgB8oR5TPlPXg0iYQEuEtff5zAgRXS+uY3dOPg2tStG3ysHUJaohD9YS2ADiA==",
       "license": "MIT",
       "dependencies": {
         "@phosphor-icons/react": "^2.1.10",

package.json

@@ -13,7 +13,7 @@
     "test:watch": "rstest --watch"
   },
   "dependencies": {
-    "@olly/modern-sk": "0.1.4-3",
+    "@olly/modern-sk": "^0.1.5",
     "@phosphor-icons/react": "^2.1.10",
     "@reduxjs/toolkit": "^2.12.0",
     "i18next": "^26.3.1",

public/config.js

@@ -0,0 +1,8 @@
+// Runtime operator configuration, read by the app before the bundle loads
+// (see src/config/env.ts). In the PROD image this file is OVERWRITTEN at
+// container start from $PUBLIC_API_BASE_URL (dockerfiles/30-runtime-config.sh),
+// so one prebuilt image can target any backend origin without a rebuild.
+//
+// This committed stub is the local-dev / build-time default: it leaves the
+// config empty so base-URL resolution falls back to the build-time env var.
+window.__APP_CONFIG__ = {};

public/manifest.webmanifest

@@ -0,0 +1,19 @@
+{
+  "name": "MCMA — Music",
+  "short_name": "MCMA",
+  "description": "Self-hosted music — control center and offline-capable player.",
+  "start_url": "/",
+  "scope": "/",
+  "display": "standalone",
+  "orientation": "any",
+  "background_color": "#0b0b0b",
+  "theme_color": "#0b0b0b",
+  "icons": [
+    {
+      "src": "/favicon.png",
+      "sizes": "128x128",
+      "type": "image/png",
+      "purpose": "any"
+    }
+  ]
+}

public/sw-core.js

@@ -0,0 +1,98 @@
+/*
+ * Service-worker core: pure helpers with NO side effects (no `self`, no
+ * `caches`, no `fetch`). Split out from `sw.js` so the tricky bits — HTTP Range
+ * parsing, LRU eviction, cache-key normalization — can be unit-tested in Node.
+ *
+ * This is an ES module: `sw.js` imports it (the SW is registered with
+ * { type: 'module' }) and tests import it natively — one source, no drift.
+ */
+
+// Bump the version to invalidate every cached blob on a breaking change.
+export const AUDIO_CACHE = 'mcma-audio-v1';
+// Synthetic same-origin key holding the LRU index ({ key: {size, lastAccess} }).
+export const INDEX_URL = '/__mcma_audio_index__';
+// Soft cap on total cached audio. LRU eviction keeps us under this.
+export const MAX_BYTES = 500 * 1024 * 1024; // 500 MB
+
+// Cover art (album/artist/playlist images) gets its own cache with a simple
+// count cap — covers are small and stable, so no per-byte LRU is needed.
+export const COVER_CACHE = 'mcma-covers-v1';
+export const MAX_COVERS = 600;
+
+// Backend stream route: /api/v1/stream/<trackId>?token=...
+const STREAM_RE = /\/stream\/([^/?#]+)/;
+
+/** The track (content) id from a stream URL, or null if it isn't one. */
+export function trackIdFromUrl(url) {
+  const m = STREAM_RE.exec(url);
+  return m ? m[1] : null;
+}
+
+/**
+ * Canonical cache key for a stream URL: origin + path, query dropped. The auth
+ * token rides in the query and rotates on refresh, so keying by content path
+ * (origin keeps two backends from colliding) makes the cache token-stable —
+ * the same track is one entry regardless of which token fetched it.
+ */
+export function cacheKeyFor(url) {
+  try {
+    const u = new URL(url);
+    return u.origin + u.pathname;
+  } catch {
+    return String(url).split('?')[0];
+  }
+}
+
+/**
+ * Parse an HTTP `Range` header against a known resource size. Returns inclusive
+ * { start, end } byte offsets, or null for "no range / serve the whole thing".
+ * Handles `bytes=a-b`, `bytes=a-` (open-ended) and `bytes=-n` (last n bytes).
+ */
+export function parseRangeHeader(rangeHeader, size) {
+  if (!rangeHeader) return null;
+  const m = /^bytes=(\d*)-(\d*)$/.exec(String(rangeHeader).trim());
+  if (!m) return null;
+  let start = m[1] === '' ? null : parseInt(m[1], 10);
+  let end = m[2] === '' ? null : parseInt(m[2], 10);
+  if (start === null && end === null) return null;
+  if (start === null) {
+    // suffix range: the final `end` bytes
+    start = Math.max(0, size - end);
+    end = size - 1;
+  } else if (end === null) {
+    end = size - 1;
+  }
+  if (Number.isNaN(start) || Number.isNaN(end)) return null;
+  if (end >= size) end = size - 1;
+  if (start < 0 || start > end) return null;
+  return { start, end };
+}
+
+/**
+ * Choose which cached entries to evict (least-recently-used first) so that the
+ * existing total plus an incoming blob fits under `maxBytes`. Returns the list
+ * of keys to delete; empty when there's already room.
+ *
+ * `index` is { [key]: { size, lastAccess } }.
+ */
+export function selectEvictions(index, incomingSize, maxBytes) {
+  let total = incomingSize;
+  for (const k in index) total += index[k].size || 0;
+  if (total <= maxBytes) return [];
+
+  const entries = Object.keys(index)
+    .map((k) => ({
+      key: k,
+      lastAccess: index[k].lastAccess || 0,
+      size: index[k].size || 0,
+    }))
+    .sort((a, b) => a.lastAccess - b.lastAccess); // oldest first
+
+  const evict = [];
+  for (const e of entries) {
+    if (total <= maxBytes) break;
+    evict.push(e.key);
+    total -= e.size;
+  }
+  return evict;
+}

public/sw.js

@@ -0,0 +1,256 @@
+/*
+ * MCMA service worker — Tier 3 offline support: audio blob cache.
+ *
+ * It sits between the app and the network for audio-stream requests only
+ * (`/stream/<id>`). The first time a track is streamed it's copied
+ * into the Cache API (keyed by content id, token stripped); afterwards — or
+ * whenever the backend is unreachable — playback is served straight from the
+ * cache, so already-heard tracks play with no network at all.
+ *
+ * Pure helpers (range parsing, LRU, key normalization) live in sw-core.js so
+ * they can be unit-tested; this file owns the side-effectful cache/network I/O.
+ * Registered as a module worker ({ type: 'module' }), so it uses ES imports.
+ */
+import {
+  AUDIO_CACHE,
+  INDEX_URL,
+  MAX_BYTES,
+  COVER_CACHE,
+  MAX_COVERS,
+  trackIdFromUrl,
+  cacheKeyFor,
+  parseRangeHeader,
+  selectEvictions,
+} from './sw-core.js';
+
+self.addEventListener('install', () => {
+  // Activate immediately on first install / update — no stale SW lingering.
+  self.skipWaiting();
+});
+
+self.addEventListener('activate', (event) => {
+  event.waitUntil(self.clients.claim());
+});
+
+self.addEventListener('fetch', (event) => {
+  const req = event.request;
+  if (req.method !== 'GET') return;
+  if (trackIdFromUrl(req.url)) {
+    event.respondWith(handleAudio(event)); // audio stream → range-aware cache
+    return;
+  }
+  if (req.destination === 'image') {
+    event.respondWith(handleImage(event)); // cover art → stale-while-revalidate
+  }
+});
+
+async function handleAudio(event) {
+  const req = event.request;
+  const key = cacheKeyFor(req.url);
+  const range = req.headers.get('range');
+  const cache = await caches.open(AUDIO_CACHE);
+
+  // 1) Serve from cache when we have it (works fully offline).
+  const cached = await cache.match(key);
+  if (cached) {
+    event.waitUntil(touch(key));
+    return range ? buildRangeResponse(cached, range) : cached.clone();
+  }
+
+  // 2) Cache miss → fetch the WHOLE file (strip Range) so we can store a
+  //    complete copy, then satisfy the original request (range-sliced if asked).
+  try {
+    const fullReq = new Request(req.url, { headers: withoutRange(req.headers) });
+    const resp = await fetch(fullReq);
+    if (isCacheable(resp)) {
+      event.waitUntil(storeInCache(key, resp.clone()));
+    }
+    return range ? buildRangeResponse(resp, range) : resp;
+  } catch {
+    // Offline and never cached — nothing we can do for this one.
+    return new Response('Offline and not cached', {
+      status: 504,
+      statusText: 'Offline',
+    });
+  }
+}
+
+/**
+ * Cover art: stale-while-revalidate. Serve the cached image instantly (so the
+ * library renders offline), refresh it in the background, and cache fresh hits.
+ * Cover URLs are token-free and stable, and `<img>` is happy with opaque
+ * cross-origin responses — so unlike audio, these cache even cross-origin.
+ */
+async function handleImage(event) {
+  const req = event.request;
+  const cache = await caches.open(COVER_CACHE);
+  const cached = await cache.match(req);
+
+  const fromNetwork = fetch(req)
+    .then((resp) => {
+      if (resp && (resp.status === 200 || resp.type === 'opaque')) {
+        return cache
+          .put(req, resp.clone())
+          .then(() => trimCovers(cache))
+          .then(() => resp);
+      }
+      return resp;
+    })
+    .catch(() => null);
+
+  if (cached) {
+    event.waitUntil(fromNetwork); // revalidate without blocking the response
+    return cached;
+  }
+  const resp = await fromNetwork;
+  return resp || new Response('', { status: 504, statusText: 'Offline' });
+}
+
+/** Keep the cover cache bounded — drop the oldest entries past the cap. */
+async function trimCovers(cache) {
+  const keys = await cache.keys();
+  const excess = keys.length - MAX_COVERS;
+  for (let i = 0; i < excess; i++) await cache.delete(keys[i]);
+}
+
+/** Only cache readable, complete 200 responses — opaque/partial are useless. */
+function isCacheable(resp) {
+  return (
+    resp.status === 200 &&
+    resp.type !== 'opaque' &&
+    resp.type !== 'opaqueredirect'
+  );
+}
+
+function withoutRange(headers) {
+  const out = new Headers();
+  for (const [k, v] of headers.entries()) {
+    if (k.toLowerCase() !== 'range') out.set(k, v);
+  }
+  return out;
+}
+
+/** Build a 206 Partial Content response by slicing a full cached/fetched body. */
+async function buildRangeResponse(response, rangeHeader) {
+  const buf = await response.clone().arrayBuffer();
+  const size = buf.byteLength;
+  const r = parseRangeHeader(rangeHeader, size);
+  const type = response.headers.get('content-type') || 'application/octet-stream';
+
+  if (!r) {
+    return new Response(buf, {
+      status: 200,
+      headers: {
+        'content-type': type,
+        'content-length': String(size),
+        'accept-ranges': 'bytes',
+      },
+    });
+  }
+
+  const sliced = buf.slice(r.start, r.end + 1);
+  return new Response(sliced, {
+    status: 206,
+    statusText: 'Partial Content',
+    headers: {
+      'content-type': type,
+      'content-range': `bytes ${r.start}-${r.end}/${size}`,
+      'content-length': String(sliced.byteLength),
+      'accept-ranges': 'bytes',
+    },
+  });
+}
+
+async function responseSize(resp) {
+  const len = resp.headers.get('content-length');
+  if (len) return Number(len);
+  const blob = await resp.blob();
+  return blob.size;
+}
+
+// --- LRU index -------------------------------------------------------------
+// The index lives as a JSON entry in the same cache. All mutations go through a
+// single serialized chain so concurrent fetch handlers can't clobber it.
+let indexChain = Promise.resolve();
+
+async function readIndex(cache) {
+  try {
+    const res = await cache.match(INDEX_URL);
+    if (!res) return {};
+    return (await res.json()) || {};
+  } catch {
+    return {};
+  }
+}
+
+function writeIndex(mutator) {
+  indexChain = indexChain
+    .then(async () => {
+      const cache = await caches.open(AUDIO_CACHE);
+      const index = await readIndex(cache);
+      await mutator(cache, index);
+      await cache.put(
+        INDEX_URL,
+        new Response(JSON.stringify(index), {
+          headers: { 'content-type': 'application/json' },
+        }),
+      );
+    })
+    .catch(() => {
+      /* keep the chain alive even if one write fails */
+    });
+  return indexChain;
+}
+
+async function storeInCache(key, resp) {
+  const size = await responseSize(resp.clone());
+  await writeIndex(async (cache, index) => {
+    for (const ek of selectEvictions(index, size, MAX_BYTES)) {
+      await cache.delete(ek);
+      delete index[ek];
+    }
+    await cache.put(key, resp);
+    index[key] = { size, lastAccess: Date.now() };
+  });
+}
+
+function touch(key) {
+  return writeIndex((_cache, index) => {
+    if (index[key]) index[key].lastAccess = Date.now();
+  });
+}
+
+// --- client messaging ------------------------------------------------------
+// The app talks to the SW over a MessageChannel: it sends a port, we reply on
+// it. Used for the offline-cache stats/controls in the UI.
+self.addEventListener('message', (event) => {
+  const data = event.data || {};
+  const reply = (result) => {
+    if (event.ports && event.ports[0]) event.ports[0].postMessage(result);
+  };
+  event.waitUntil(
+    (async () => {
+      try {
+        const cache = await caches.open(AUDIO_CACHE);
+        const index = await readIndex(cache);
+        if (data.type === 'STATS') {
+          const keys = Object.keys(index);
+          const bytes = keys.reduce((s, k) => s + (index[k].size || 0), 0);
+          reply({ count: keys.length, bytes, maxBytes: MAX_BYTES });
+        } else if (data.type === 'HAS') {
+          reply({ cached: !!index[cacheKeyFor(data.url)] });
+        } else if (data.type === 'CLEAR') {
+          await Promise.all([
+            caches.delete(AUDIO_CACHE),
+            caches.delete(COVER_CACHE),
+          ]);
+          reply({ ok: true });
+        } else {
+          reply({ error: 'unknown-message' });
+        }
+      } catch (e) {
+        reply({ error: String(e) });
+      }
+    })(),
+  );
+});

rsbuild.config.ts

@@ -32,5 +32,38 @@ export default defineConfig({
   // no manual source.define needed. See src/config/env.ts.
   html: {
     title: 'MCMA',
+    // PWA: link the manifest + declare theme/icon so the browser offers
+    // "Install app". The service worker (audio offline cache) is registered
+    // from src/index.tsx, not here.
+    tags: [
+      // Theme bootstrap — runs inline before first paint to kill the flash of
+      // white on a dark-themed load. Mirrors modern-sk's own logic exactly
+      // (localStorage 'modern-sk-theme' || 'dark' → data-theme on <html>), so
+      // there's no second flip when <ThemeProvider> mounts. Inline (not an
+      // external file) so it costs zero round-trips.
+      {
+        tag: 'script',
+        children:
+          "(function(){try{var t=localStorage.getItem('modern-sk-theme')||'dark';document.documentElement.setAttribute('data-theme',t);}catch(e){}})();",
+        head: true,
+        append: false,
+      },
+      // Runtime operator config. A classic (non-deferred) head script, so it
+      // runs before the deferred app bundle and window.__APP_CONFIG__ is set by
+      // the time src/config/env.ts reads it. Served from public/ in dev and
+      // overwritten from $PUBLIC_API_BASE_URL at container start in prod.
+      {
+        tag: 'script',
+        attrs: { src: '/config.js' },
+        head: true,
+        append: false,
+      },
+      {
+        tag: 'link',
+        attrs: { rel: 'manifest', href: '/manifest.webmanifest' },
+      },
+      { tag: 'meta', attrs: { name: 'theme-color', content: '#0b0b0b' } },
+      { tag: 'link', attrs: { rel: 'apple-touch-icon', href: '/favicon.png' } },
+    ],
   },
 });

src/api/baseQuery.ts

@@ -34,24 +34,23 @@ export const baseQueryWithReauth: BaseQueryFn<
         {
           url: '/auth/refresh',
           method: 'POST',
-          body: { refreshToken },
+          body: { refresh_token: refreshToken },
         },
         api,
         extraOptions,
       );
 
       if (refreshResult.data) {
-        const {
+        // Backend wire format is snake_case with no TTL (see auth.ts adapter).
-          accessToken,
+        const { access_token, refresh_token } = refreshResult.data as {
-          refreshToken: newRefresh,
+          access_token: string;
-          expiresIn,
+          refresh_token: string;
-        } = refreshResult.data as {
-          accessToken: string;
-          refreshToken: string;
-          expiresIn: number;
         };
         api.dispatch(
-          setTokens({ accessToken, refreshToken: newRefresh, expiresIn }),
+          setTokens({
+            accessToken: access_token,
+            refreshToken: refresh_token,
+          }),
         );
         result = await rawBaseQuery()(args, api, extraOptions);
       } else {

src/api/endpoints/admin.ts

@@ -1,33 +1,44 @@
 import { api } from '../index';
+import { toUser, type RawUser } from '../mappers';
 import type { User } from '../types';
 
+/**
+ * Admin user management. The backend models authorization as `is_superuser` /
+ * `is_active` (no `role`/`email`); `toUser` maps superuser→role for the UI and
+ * the mutations translate role back to `is_superuser` on the way out.
+ */
 export const adminApi = api.injectEndpoints({
   endpoints: (build) => ({
     getUsers: build.query<User[], void>({
       query: () => '/admin/users',
+      transformResponse: (raw: RawUser[]) => raw.map(toUser),
       providesTags: ['User'],
     }),
     createUser: build.mutation<
       User,
-      {
+      { username: string; password: string; role: 'admin' | 'user' }
-        username: string;
-        password: string;
-        email?: string;
-        role: 'admin' | 'user';
-      }
     >({
-      query: (body) => ({ url: '/admin/users', method: 'POST', body }),
+      query: ({ username, password, role }) => ({
+        url: '/admin/users',
+        method: 'POST',
+        body: { username, password, is_superuser: role === 'admin' },
+      }),
+      transformResponse: (raw: RawUser) => toUser(raw),
       invalidatesTags: ['User'],
     }),
     updateUser: build.mutation<
       User,
-      { id: string; role?: 'admin' | 'user'; email?: string }
+      { id: string; role?: 'admin' | 'user'; isActive?: boolean }
     >({
-      query: ({ id, ...body }) => ({
+      query: ({ id, role, isActive }) => ({
         url: `/admin/users/${id}`,
         method: 'PATCH',
-        body,
+        body: {
+          is_superuser: role === undefined ? undefined : role === 'admin',
+          is_active: isActive,
+        },
       }),
+      transformResponse: (raw: RawUser) => toUser(raw),
       invalidatesTags: ['User'],
     }),
     deleteUser: build.mutation<void, string>({

src/api/endpoints/auth.ts

@@ -1,26 +1,110 @@
 import { api } from '../index';
-import type { LoginRequest, LoginResponse } from '../types';
+import { toUser, type RawUser } from '../mappers';
+import type {
+  AuthTokens,
+  LoginRequest,
+  LoginResponse,
+  RegisterRequest,
+  User,
+} from '../types';
+
+/**
+ * Auth seam over the backend's wire format: tokens-only login + a separate
+ * `/auth/me` for the user. Token mapping lives here; user mapping is shared with
+ * the admin endpoints via `toUser` in `mappers.ts`.
+ */
+
+/** `/auth/login` & `/auth/refresh` response shape. */
+interface RawTokenResponse {
+  access_token: string;
+  refresh_token: string;
+  token_type?: string;
+}
+
+const toTokens = (raw: RawTokenResponse): AuthTokens => ({
+  accessToken: raw.access_token,
+  refreshToken: raw.refresh_token,
+  // No TTL on the wire — expiry is 401-driven (see baseQuery reauth).
+});
 
 export const authApi = api.injectEndpoints({
   endpoints: (build) => ({
+    // Login is a two-call flow: POST /auth/login yields tokens, then GET
+    // /auth/me resolves the user. A queryFn chains both so callers get the
+    // unified { user, tokens } the UI expects in one await.
     login: build.mutation<LoginResponse, LoginRequest>({
-      query: (body) => ({ url: '/auth/login', method: 'POST', body }),
+      async queryFn(body, _api, _extra, baseQuery) {
+        const tokenRes = await baseQuery({
+          url: '/auth/login',
+          method: 'POST',
+          body,
+        });
+        if (tokenRes.error) return { error: tokenRes.error };
+        const tokens = toTokens(tokenRes.data as RawTokenResponse);
+
+        // The access token isn't in the store yet, so attach it explicitly —
+        // baseQuery's prepareHeaders only injects what's already in auth state.
+        const meRes = await baseQuery({
+          url: '/auth/me',
+          headers: { Authorization: `Bearer ${tokens.accessToken}` },
+        });
+        if (meRes.error) return { error: meRes.error };
+        const user = toUser(meRes.data as RawUser);
+
+        return { data: { user, tokens } };
+      },
     }),
-    logout: build.mutation<void, void>({
+    // Sign-up mirrors login: POST /auth/register returns a token pair (the
-      query: () => ({ url: '/auth/logout', method: 'POST' }),
+    // backend logs the new account straight in), then GET /auth/me resolves the
+    // user — so the UI gets the same unified { user, tokens } as login.
+    register: build.mutation<LoginResponse, RegisterRequest>({
+      async queryFn(body, _api, _extra, baseQuery) {
+        const tokenRes = await baseQuery({
+          url: '/auth/register',
+          method: 'POST',
+          body,
+        });
+        if (tokenRes.error) return { error: tokenRes.error };
+        const tokens = toTokens(tokenRes.data as RawTokenResponse);
+
+        const meRes = await baseQuery({
+          url: '/auth/me',
+          headers: { Authorization: `Bearer ${tokens.accessToken}` },
+        });
+        if (meRes.error) return { error: meRes.error };
+        const user = toUser(meRes.data as RawUser);
+
+        return { data: { user, tokens } };
+      },
     }),
-    refreshToken: build.mutation<
+    logout: build.mutation<void, { refreshToken: string }>({
-      { accessToken: string; refreshToken: string; expiresIn: number },
+      query: ({ refreshToken }) => ({
-      { refreshToken: string }
+        url: '/auth/logout',
-    >({
+        method: 'POST',
-      query: (body) => ({ url: '/auth/refresh', method: 'POST', body }),
+        body: { refresh_token: refreshToken },
+      }),
     }),
-    me: build.query<import('../types').User, void>({
+    refreshToken: build.mutation<AuthTokens, { refreshToken: string }>({
+      query: ({ refreshToken }) => ({
+        url: '/auth/refresh',
+        method: 'POST',
+        body: { refresh_token: refreshToken },
+      }),
+      transformResponse: (raw: RawTokenResponse) => toTokens(raw),
+    }),
+    me: build.query<User, void>({
       query: () => '/auth/me',
+      transformResponse: (raw: RawUser) => toUser(raw),
       providesTags: ['User'],
     }),
   }),
   overrideExisting: false,
 });
 
-export const { useLoginMutation, useLogoutMutation, useMeQuery } = authApi;
+export const {
+  useLoginMutation,
+  useRegisterMutation,
+  useLogoutMutation,
+  useRefreshTokenMutation,
+  useMeQuery,
+} = authApi;

src/api/endpoints/downloads.ts

@@ -1,6 +1,12 @@
 import { api } from '../index';
 import type { DownloadJob } from '../types';
 
+// NOTE: the backend `/downloads` routes are still unimplemented stubs (they
+// return no body / no schema). The request shapes below are provisional and the
+// responses will need the same snake→camel mapper treatment as library/playlists
+// (see `mappers.ts`) once the backend defines DownloadJob's wire format. Do not
+// wire these into the UI until then.
+
 export const downloadsApi = api.injectEndpoints({
   endpoints: (build) => ({
     getDownloads: build.query<

src/api/endpoints/library.ts

@@ -1,16 +1,61 @@
 import { api } from '../index';
+import {
+  toAlbum,
+  toArtist,
+  toMetadataMatch,
+  toPage,
+  toTrack,
+  type RawAlbum,
+  type RawArtist,
+  type RawMetadataMatch,
+  type RawPaged,
+  type RawTrack,
+} from '../mappers';
 import type {
   Track,
   Album,
   Artist,
+  MetadataEdit,
+  MetadataMatch,
   PaginatedResponse,
   LibraryFilters,
 } from '../types';
 
+// The backend sorts on a small allow-list; map the UI's sort keys onto it
+// (album/year aren't sortable server-side yet → fall back to recency).
+const SORT_BY: Record<NonNullable<LibraryFilters['sortBy']>, string> = {
+  title: 'title',
+  artist: 'artist',
+  album: 'created_at',
+  year: 'created_at',
+  dateAdded: 'created_at',
+};
+
+/** UI page/pageSize → backend limit/offset. */
+function paging(page?: number, pageSize?: number) {
+  const size = pageSize ?? 50;
+  return { limit: size, offset: ((page ?? 1) - 1) * size };
+}
+
+function trackParams(f: LibraryFilters) {
+  return {
+    q: f.search,
+    artist_id: f.artistId,
+    album_id: f.albumId,
+    sort_by: f.sortBy ? SORT_BY[f.sortBy] : undefined,
+    order: f.sortOrder,
+    ...paging(f.page, f.pageSize),
+  };
+}
+
 export const libraryApi = api.injectEndpoints({
   endpoints: (build) => ({
     getTracks: build.query<PaginatedResponse<Track>, LibraryFilters | void>({
-      query: (filters) => ({ url: '/library/tracks', params: filters ?? {} }),
+      query: (filters) => ({
+        url: '/tracks',
+        params: trackParams(filters ?? {}),
+      }),
+      transformResponse: (raw: RawPaged<RawTrack>) => toPage(raw, toTrack),
       providesTags: (result) =>
         result
           ? [
@@ -20,7 +65,8 @@ export const libraryApi = api.injectEndpoints({
           : ['Track'],
     }),
     getTrack: build.query<Track, string>({
-      query: (id) => `/library/tracks/${id}`,
+      query: (id) => `/tracks/${id}`,
+      transformResponse: (raw: RawTrack) => toTrack(raw),
       providesTags: (_r, _e, id) => [{ type: 'Track', id }],
     }),
     getAlbums: build.query<
@@ -32,7 +78,15 @@ export const libraryApi = api.injectEndpoints({
         pageSize?: number;
       } | void
     >({
-      query: (params) => ({ url: '/library/albums', params: params ?? {} }),
+      query: (p) => ({
+        url: '/albums',
+        params: {
+          q: p?.search,
+          artist_id: p?.artistId,
+          ...paging(p?.page, p?.pageSize),
+        },
+      }),
+      transformResponse: (raw: RawPaged<RawAlbum>) => toPage(raw, toAlbum),
       providesTags: (result) =>
         result
           ? [
@@ -42,11 +96,13 @@ export const libraryApi = api.injectEndpoints({
           : ['Album'],
     }),
     getAlbum: build.query<Album, string>({
-      query: (id) => `/library/albums/${id}`,
+      query: (id) => `/albums/${id}`,
+      transformResponse: (raw: RawAlbum) => toAlbum(raw),
       providesTags: (_r, _e, id) => [{ type: 'Album', id }],
     }),
     getAlbumTracks: build.query<Track[], string>({
-      query: (albumId) => `/library/albums/${albumId}/tracks`,
+      query: (albumId) => `/albums/${albumId}/tracks`,
+      transformResponse: (raw: RawPaged<RawTrack>) => raw.items.map(toTrack),
       providesTags: (_r, _e, albumId) => [
         { type: 'Album', id: albumId },
         'Track',
@@ -56,7 +112,11 @@ export const libraryApi = api.injectEndpoints({
       PaginatedResponse<Artist>,
       { search?: string; page?: number; pageSize?: number } | void
     >({
-      query: (params) => ({ url: '/library/artists', params: params ?? {} }),
+      query: (p) => ({
+        url: '/artists',
+        params: { q: p?.search, ...paging(p?.page, p?.pageSize) },
+      }),
+      transformResponse: (raw: RawPaged<RawArtist>) => toPage(raw, toArtist),
       providesTags: (result) =>
         result
           ? [
@@ -69,23 +129,77 @@ export const libraryApi = api.injectEndpoints({
           : ['Artist'],
     }),
     getArtist: build.query<Artist, string>({
-      query: (id) => `/library/artists/${id}`,
+      query: (id) => `/artists/${id}`,
+      transformResponse: (raw: RawArtist) => toArtist(raw),
       providesTags: (_r, _e, id) => [{ type: 'Artist', id }],
     }),
     getArtistAlbums: build.query<Album[], string>({
-      query: (artistId) => `/library/artists/${artistId}/albums`,
+      query: (artistId) => `/artists/${artistId}/albums`,
+      transformResponse: (raw: RawPaged<RawAlbum>) => raw.items.map(toAlbum),
       providesTags: (_r, _e, artistId) => [
         { type: 'Artist', id: artistId },
         'Album',
       ],
     }),
+    getArtistTracks: build.query<Track[], string>({
+      query: (artistId) => `/artists/${artistId}/tracks`,
+      transformResponse: (raw: RawPaged<RawTrack>) => raw.items.map(toTrack),
+      providesTags: (_r, _e, artistId) => [
+        { type: 'Artist', id: artistId },
+        'Track',
+      ],
+    }),
     searchLibrary: build.query<
       { tracks: Track[]; albums: Album[]; artists: Artist[] },
       string
     >({
-      query: (q) => ({ url: '/library/search', params: { q } }),
+      query: (q) => ({ url: '/search/library', params: { q } }),
+      transformResponse: (raw: {
+        tracks: RawTrack[];
+        albums: RawAlbum[];
+        artists: RawArtist[];
+      }) => ({
+        tracks: raw.tracks.map(toTrack),
+        albums: raw.albums.map(toAlbum),
+        artists: raw.artists.map(toArtist),
+      }),
       providesTags: ['Track', 'Album', 'Artist'],
     }),
+    getMetadataMatches: build.query<MetadataMatch[], string>({
+      query: (trackId) => `/tracks/${trackId}/metadata/matches`,
+      transformResponse: (raw: { items: RawMetadataMatch[] }) =>
+        raw.items.map(toMetadataMatch),
+    }),
+    applyMetadata: build.mutation<
+      Track,
+      { trackId: string; edit: MetadataEdit }
+    >({
+      query: ({ trackId, edit }) => ({
+        url: `/tracks/${trackId}/metadata`,
+        method: 'PUT',
+        body: {
+          title: edit.title,
+          artist_name: edit.artistName,
+          album_title: edit.albumTitle,
+          year: edit.year,
+          genre: edit.genre,
+          track_number: edit.trackNumber,
+        },
+      }),
+      transformResponse: (raw: RawTrack) => toTrack(raw),
+      invalidatesTags: (_r, _e, { trackId }) => [
+        { type: 'Track', id: trackId },
+        'Album',
+        'Artist',
+      ],
+    }),
+    enrichTrack: build.mutation<{ track_id: string; job_id: string }, string>({
+      query: (trackId) => ({
+        url: `/tracks/${trackId}/metadata/enrich`,
+        method: 'POST',
+      }),
+      invalidatesTags: (_r, _e, trackId) => [{ type: 'Track', id: trackId }],
+    }),
   }),
   overrideExisting: false,
 });
@@ -99,5 +213,9 @@ export const {
   useGetArtistsQuery,
   useGetArtistQuery,
   useGetArtistAlbumsQuery,
+  useGetArtistTracksQuery,
   useSearchLibraryQuery,
+  useLazyGetMetadataMatchesQuery,
+  useApplyMetadataMutation,
+  useEnrichTrackMutation,
 } = libraryApi;

src/api/endpoints/likes.ts

@@ -1,20 +1,68 @@
 import { api } from '../index';
 
+/**
+ * Likes are an append-only event-log on the backend: state changes by POSTing a
+ * new `{track_id, value}` event, never by PUT/DELETE on a boolean. "Unlike" is
+ * just a `neutral` event superseding the prior `like`.
+ */
+type LikeValue = 'like' | 'dislike' | 'neutral';
+
+interface RawLikeState {
+  track_id: string;
+  value: LikeValue;
+  updated_at: string;
+}
+
+export interface LikeState {
+  trackId: string;
+  value: LikeValue;
+  updatedAt: string;
+}
+
+const toLikeState = (r: RawLikeState): LikeState => ({
+  trackId: r.track_id,
+  value: r.value,
+  updatedAt: r.updated_at,
+});
+
 export const likesApi = api.injectEndpoints({
   endpoints: (build) => ({
-    likeTrack: build.mutation<void, string>({
+    setLike: build.mutation<LikeState, { trackId: string; value: LikeValue }>({
-      query: (trackId) => ({ url: `/likes/tracks/${trackId}`, method: 'PUT' }),
+      query: ({ trackId, value }) => ({
-      invalidatesTags: (_r, _e, id) => ['Like', { type: 'Track', id }],
+        url: '/likes',
-    }),
+        method: 'POST',
-    unlikeTrack: build.mutation<void, string>({
+        body: { track_id: trackId, value },
-      query: (trackId) => ({
-        url: `/likes/tracks/${trackId}`,
-        method: 'DELETE',
       }),
-      invalidatesTags: (_r, _e, id) => ['Like', { type: 'Track', id }],
+      transformResponse: (raw: RawLikeState) => toLikeState(raw),
+      invalidatesTags: (_r, _e, { trackId }) => [
+        'Like',
+        { type: 'Track', id: trackId },
+      ],
+    }),
+    // Latest like state for a set of tracks (drives like buttons in lists).
+    getLikesState: build.query<LikeState[], string[]>({
+      query: (trackIds) => ({
+        url: '/likes/state',
+        params: { track_ids: trackIds.join(',') },
+      }),
+      transformResponse: (raw: RawLikeState[]) => raw.map(toLikeState),
+      providesTags: ['Like'],
     }),
   }),
   overrideExisting: false,
 });
 
-export const { useLikeTrackMutation, useUnlikeTrackMutation } = likesApi;
+const { useSetLikeMutation, useGetLikesStateQuery } = likesApi;
+
+/** Convenience hook preserving the like/unlike call sites. */
+export function useLikeActions() {
+  const [setLike, state] = useSetLikeMutation();
+  return {
+    like: (trackId: string) => setLike({ trackId, value: 'like' }),
+    unlike: (trackId: string) => setLike({ trackId, value: 'neutral' }),
+    dislike: (trackId: string) => setLike({ trackId, value: 'dislike' }),
+    state,
+  };
+}
+
+export { useSetLikeMutation, useGetLikesStateQuery };

src/api/endpoints/playlists.ts

@@ -1,36 +1,61 @@
 import { api } from '../index';
+import {
+  toPage,
+  toPlaylist,
+  toTrack,
+  type RawPaged,
+  type RawPlaylist,
+  type RawTrack,
+} from '../mappers';
 import type { Playlist, PlaylistTrack, PaginatedResponse } from '../types';
 
 export const playlistsApi = api.injectEndpoints({
   endpoints: (build) => ({
     getPlaylists: build.query<PaginatedResponse<Playlist>, void>({
       query: () => '/playlists',
+      transformResponse: (raw: RawPaged<RawPlaylist>) =>
+        toPage(raw, toPlaylist),
       providesTags: ['Playlist'],
     }),
     getPlaylist: build.query<Playlist, string>({
       query: (id) => `/playlists/${id}`,
+      transformResponse: (raw: RawPlaylist) => toPlaylist(raw),
       providesTags: (_r, _e, id) => [{ type: 'Playlist', id }],
     }),
     getPlaylistTracks: build.query<PlaylistTrack[], string>({
       query: (id) => `/playlists/${id}/tracks`,
+      // The backend returns plain tracks in playlist order; position/addedAt
+      // aren't on TrackOut, so derive position from order and default addedAt.
+      transformResponse: (raw: RawPaged<RawTrack>) =>
+        raw.items.map((r, i) => ({
+          ...toTrack(r),
+          position: i,
+          addedAt: r.created_at,
+        })),
       providesTags: (_r, _e, id) => [{ type: 'Playlist', id }, 'Track'],
     }),
     createPlaylist: build.mutation<
       Playlist,
-      { name: string; description?: string; isPublic?: boolean }
+      { name: string; description?: string }
     >({
-      query: (body) => ({ url: '/playlists', method: 'POST', body }),
+      query: ({ name, description }) => ({
+        url: '/playlists',
+        method: 'POST',
+        body: { name, description },
+      }),
+      transformResponse: (raw: RawPlaylist) => toPlaylist(raw),
       invalidatesTags: ['Playlist'],
     }),
     updatePlaylist: build.mutation<
       Playlist,
-      { id: string; name?: string; description?: string; isPublic?: boolean }
+      { id: string; name?: string; description?: string }
     >({
-      query: ({ id, ...body }) => ({
+      query: ({ id, name, description }) => ({
         url: `/playlists/${id}`,
         method: 'PATCH',
-        body,
+        body: { name, description },
       }),
+      transformResponse: (raw: RawPlaylist) => toPlaylist(raw),
       invalidatesTags: (_r, _e, { id }) => [{ type: 'Playlist', id }],
     }),
     deletePlaylist: build.mutation<void, string>({
@@ -39,12 +64,12 @@ export const playlistsApi = api.injectEndpoints({
     }),
     addTrackToPlaylist: build.mutation<
       void,
-      { playlistId: string; trackId: string }
+      { playlistId: string; trackId: string; position?: number }
     >({
-      query: ({ playlistId, trackId }) => ({
+      query: ({ playlistId, trackId, position }) => ({
         url: `/playlists/${playlistId}/tracks`,
         method: 'POST',
-        body: { trackId },
+        body: { track_id: trackId, position },
       }),
       invalidatesTags: (_r, _e, { playlistId }) => [
         { type: 'Playlist', id: playlistId },
@@ -52,10 +77,10 @@ export const playlistsApi = api.injectEndpoints({
     }),
     removeTrackFromPlaylist: build.mutation<
       void,
-      { playlistId: string; trackId: string; position: number }
+      { playlistId: string; trackId: string }
     >({
-      query: ({ playlistId, position }) => ({
+      query: ({ playlistId, trackId }) => ({
-        url: `/playlists/${playlistId}/tracks/${position}`,
+        url: `/playlists/${playlistId}/tracks/${trackId}`,
         method: 'DELETE',
       }),
       invalidatesTags: (_r, _e, { playlistId }) => [

src/api/endpoints/storage.ts

@@ -1,6 +1,13 @@
 import { api } from '../index';
 import type { StorageStats } from '../types';
 
+// NOTE: the backend `/storage` routes are still unimplemented stubs (no body /
+// no schema), and the real paths differ from these placeholders (`GET /storage`,
+// `/storage/duplicates`, `/storage/broken`, `/storage/missing-metadata`,
+// `POST /storage/cleanup`). Re-point paths and add snake→camel mappers (see
+// `mappers.ts`) once the backend defines the storage response shapes; until then
+// these are provisional and unused by the UI.
+
 export const storageApi = api.injectEndpoints({
   endpoints: (build) => ({
     getStorageStats: build.query<StorageStats, void>({

src/api/endpoints/streaming.ts

@@ -1,8 +1,13 @@
 import { getApiBaseUrl } from '../../config/runtime-config';
 
+/**
+ * Audio stream URL for the `<audio>` element. The access token rides as a query
+ * param because `<audio>` can't send an `Authorization` header; the backend
+ * accepts `?token=` on `GET /stream/{id}` for exactly this reason.
+ */
 export function getStreamUrl(trackId: string, token: string): string {
   const base = getApiBaseUrl();
-  return `${base}/streaming/tracks/${trackId}?token=${encodeURIComponent(token)}`;
+  return `${base}/stream/${trackId}?token=${encodeURIComponent(token)}`;
 }
 
 export function getCoverUrl(artUrl: string | undefined): string | undefined {
@@ -12,3 +17,18 @@ export function getCoverUrl(artUrl: string | undefined): string | undefined {
   const base = getApiBaseUrl();
   return `${base}${artUrl}`;
 }
+
+/**
+ * Cover image URL for a track, served by `GET /tracks/{id}/cover`. Like the
+ * audio stream, an `<img>` can't send an `Authorization` header, so the access
+ * token rides as `?token=`. Returns undefined when the track has no cover.
+ */
+export function getTrackCoverUrl(
+  trackId: string,
+  token: string,
+  hasCover: boolean,
+): string | undefined {
+  if (!hasCover) return undefined;
+  const base = getApiBaseUrl();
+  return `${base}/tracks/${trackId}/cover?token=${encodeURIComponent(token)}`;
+}

src/api/index.ts

@@ -1,5 +1,6 @@
 import { createApi } from '@reduxjs/toolkit/query/react';
 import { baseQueryWithReauth } from './baseQuery';
+import { REHYDRATE_API, type RehydrateApiPayload } from './rehydrate';
 
 export const api = createApi({
   reducerPath: 'api',
@@ -14,5 +15,16 @@ export const api = createApi({
     'User',
     'Storage',
   ],
+  // Tier 2 offline: seed the cache from the persisted snapshot dispatched at
+  // startup (see `store/rtkqPersist.ts`). Returning the saved queries/mutations
+  // lets the last-seen library render before — or instead of — any network call.
+  extractRehydrationInfo(action) {
+    if (action.type === REHYDRATE_API) {
+      // The api reducer reads `queries`/`mutations` off this and restores any
+      // fulfilled entries; pending/rejected ones are ignored automatically.
+      return action.payload as RehydrateApiPayload as never;
+    }
+    return undefined;
+  },
   endpoints: () => ({}),
 });

src/api/mappers.ts

@@ -0,0 +1,219 @@
+/**
+ * Backend-contract adapters: the single place where the backend's wire format
+ * (snake_case, lean `*Out` schemas, `{items,total,limit,offset}` paging) is
+ * translated into the UI's internal camelCase domain types from `types.ts`.
+ *
+ * The endpoint files (`endpoints/*.ts`) own *paths and params*; this module owns
+ * *shape*. Swapping or mocking a backend means rewriting the mappers here —
+ * nothing in components, slices, or `types.ts` changes.
+ *
+ * Where the backend's lean schema omits a field the UI type carries (cover art,
+ * liked state, durations on albums…), the mapper fills a safe client default and
+ * says why inline. Those defaults are the contract's current edges, not bugs.
+ */
+import type {
+  Album,
+  Artist,
+  MetadataMatch,
+  MetadataStatus,
+  PaginatedResponse,
+  Playlist,
+  Track,
+  User,
+} from './types';
+
+const METADATA_STATUSES: readonly MetadataStatus[] = [
+  'pending',
+  'enriched',
+  'failed',
+  'manual',
+];
+
+/** Map the backend's free-form status string onto the UI union, defaulting any
+ * unknown value to `pending` (a safe "not yet identified" state). */
+const toMetadataStatus = (raw: string): MetadataStatus =>
+  (METADATA_STATUSES as readonly string[]).includes(raw)
+    ? (raw as MetadataStatus)
+    : 'pending';
+
+// ---- raw wire shapes (snake_case, exactly as the backend emits) ----
+
+export interface RawPaged<T> {
+  items: T[];
+  total: number;
+  limit: number;
+  offset: number;
+}
+
+export interface RawUser {
+  id: string;
+  username: string;
+  is_superuser: boolean;
+  is_active: boolean;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface RawTrack {
+  id: string;
+  title: string;
+  artist_id: string;
+  artist_name: string;
+  album_id: string | null;
+  album_title: string | null;
+  duration_seconds: number | null;
+  file_format: string;
+  file_size: number;
+  genre: string | null;
+  year: number | null;
+  track_number: number | null;
+  metadata_status: string;
+  metadata_error: string | null;
+  enriched_at: string | null;
+  has_cover: boolean;
+  source: string;
+  created_at: string;
+}
+
+/** One AcoustID candidate, as returned by `GET /tracks/{id}/metadata/matches`. */
+export interface RawMetadataMatch {
+  acoustid: string;
+  score: number;
+  recording_mbid: string | null;
+  release_group_mbid: string | null;
+  title: string | null;
+  artist: string | null;
+  album: string | null;
+  year: number | null;
+}
+
+export interface RawAlbum {
+  id: string;
+  title: string;
+  artist_id: string;
+  artist_name: string;
+  year: number | null;
+  track_count: number;
+  created_at: string;
+}
+
+export interface RawArtist {
+  id: string;
+  name: string;
+  album_count: number;
+  track_count: number;
+  created_at: string;
+}
+
+export interface RawPlaylist {
+  id: string;
+  name: string;
+  description: string | null;
+  owner_id: string;
+  version: number;
+  track_count: number;
+  created_at: string;
+}
+
+// ---- mappers ----
+
+export const toUser = (r: RawUser): User => ({
+  id: r.id,
+  username: r.username,
+  // MVP role model: superuser → admin, everyone else → user.
+  role: r.is_superuser ? 'admin' : 'user',
+  createdAt: r.created_at,
+});
+
+export const toTrack = (r: RawTrack): Track => ({
+  id: r.id,
+  title: r.title,
+  artistId: r.artist_id,
+  artistName: r.artist_name,
+  albumId: r.album_id ?? '',
+  albumTitle: r.album_title ?? '',
+  // `has_cover` says a cover exists; the actual URL (which needs a `?token=`) is
+  // built in the component from the track id — see `getTrackCoverUrl`. Keep
+  // `albumArtUrl` undefined so callers fall back to generated tile art.
+  albumArtUrl: undefined,
+  hasCover: r.has_cover,
+  durationMs: (r.duration_seconds ?? 0) * 1000,
+  // The lean TrackOut carries no availability/like state: a track returned by
+  // the library is on the server, and per-track like state comes from /likes.
+  availability: 'server',
+  metadataStatus: toMetadataStatus(r.metadata_status),
+  metadataError: r.metadata_error ?? undefined,
+  genre: r.genre ?? undefined,
+  year: r.year ?? undefined,
+  trackNumber: r.track_number ?? undefined,
+  liked: false,
+  format: r.file_format,
+  fileSize: r.file_size,
+  source: r.source,
+  createdAt: r.created_at,
+  enrichedAt: r.enriched_at ?? undefined,
+});
+
+export const toMetadataMatch = (r: RawMetadataMatch): MetadataMatch => ({
+  acoustid: r.acoustid,
+  score: r.score,
+  recordingMbid: r.recording_mbid ?? undefined,
+  releaseGroupMbid: r.release_group_mbid ?? undefined,
+  title: r.title ?? undefined,
+  artist: r.artist ?? undefined,
+  album: r.album ?? undefined,
+  year: r.year ?? undefined,
+});
+
+export const toAlbum = (r: RawAlbum): Album => ({
+  id: r.id,
+  title: r.title,
+  artistId: r.artist_id,
+  artistName: r.artist_name,
+  artUrl: undefined,
+  year: r.year ?? undefined,
+  trackCount: r.track_count,
+  // AlbumOut has no aggregate duration; computed client-side from tracks when
+  // an album is opened.
+  totalDurationMs: 0,
+});
+
+export const toArtist = (r: RawArtist): Artist => ({
+  id: r.id,
+  name: r.name,
+  artUrl: undefined,
+  albumCount: r.album_count,
+  trackCount: r.track_count,
+});
+
+export const toPlaylist = (r: RawPlaylist): Playlist => ({
+  id: r.id,
+  name: r.name,
+  description: r.description ?? undefined,
+  ownerId: r.owner_id,
+  trackCount: r.track_count,
+  totalDurationMs: 0,
+  // No visibility concept on the backend yet — default private.
+  isPublic: false,
+  createdAt: r.created_at,
+  // PlaylistOut omits updated_at; mirror created_at until it's added.
+  updatedAt: r.created_at,
+});
+
+/**
+ * Translate the backend's `{items,total,limit,offset}` envelope into the UI's
+ * `{items,total,page,pageSize,hasMore}`, mapping each element.
+ */
+export const toPage = <R, T>(
+  raw: RawPaged<R>,
+  map: (r: R) => T,
+): PaginatedResponse<T> => {
+  const pageSize = raw.limit || raw.items.length || 1;
+  return {
+    items: raw.items.map(map),
+    total: raw.total,
+    page: Math.floor(raw.offset / pageSize) + 1,
+    pageSize,
+    hasMore: raw.offset + raw.items.length < raw.total,
+  };
+};

src/api/rehydrate.ts

@@ -0,0 +1,25 @@
+import { createAction } from '@reduxjs/toolkit';
+
+/*
+ * Tier 2 offline support contract. RTK Query can seed its cache from a
+ * persisted snapshot via `extractRehydrationInfo` (see `api/index.ts`). We use
+ * a single action whose payload is the previously-saved api slice state; the
+ * api reducer pulls `queries`/`mutations` out of it on startup so last-seen
+ * library data renders read-only while the backend is unreachable.
+ *
+ * The type string lives here (not in the store) so `api/index.ts` can match it
+ * without importing from the store layer (which would create a cycle).
+ */
+export const REHYDRATE_API = 'api/rehydrate';
+
+export interface RehydrateApiPayload {
+  queries: Record<string, unknown>;
+  mutations: Record<string, unknown>;
+  // RTKQ's invalidation slice reads `provided.tags`/`provided.keys` during
+  // rehydration (it does `Object.entries(provided.tags ?? {})`), so `provided`
+  // must be an object — a bare `{ queries, mutations }` makes it crash on
+  // `provided.tags` of undefined. Always present; empty objects are valid.
+  provided: { tags: Record<string, unknown>; keys: Record<string, unknown> };
+}
+
+export const rehydrateApi = createAction<RehydrateApiPayload>(REHYDRATE_API);

src/api/types.ts

@@ -1,5 +1,13 @@
 export type TrackAvailability = 'server' | 'downloading' | 'error' | 'missing';
 
+/**
+ * Metadata-enrichment state, distinct from file `availability`. `pending` = the
+ * worker hasn't finished (or hasn't started); `enriched` = identity found;
+ * `failed` = no match / a worker error (see `metadataError`); `manual` = user-
+ * edited and never auto-overwritten.
+ */
+export type MetadataStatus = 'pending' | 'enriched' | 'failed' | 'manual';
+
 export interface Track {
   id: string;
   title: string;
@@ -8,16 +16,26 @@ export interface Track {
   albumId: string;
   albumTitle: string;
   albumArtUrl?: string;
+  hasCover: boolean;
   durationMs: number;
   trackNumber?: number;
   discNumber?: number;
   year?: number;
   genre?: string;
   availability: TrackAvailability;
+  metadataStatus: MetadataStatus;
+  /** Human-readable reason the last enrichment run set `failed`; else undefined. */
+  metadataError?: string;
   fileSize?: number;
   format?: string;
   bitrate?: number;
   liked: boolean;
+  /** Where the track entered the library (e.g. `upload`, `local_folder`). */
+  source?: string;
+  /** ISO timestamp the track was added to the library. */
+  createdAt?: string;
+  /** ISO timestamp the last successful enrichment ran; undefined if never. */
+  enrichedAt?: string;
 }
 
 export interface Album {
@@ -98,7 +116,9 @@ export interface User {
 export interface AuthTokens {
   accessToken: string;
   refreshToken: string;
-  expiresIn: number;
+  // Optional: the backend's TokenResponse carries no TTL — expiry is driven by
+  // 401→refresh, not a client-side clock. Present only if a backend supplies it.
+  expiresIn?: number;
 }
 
 export interface LoginRequest {
@@ -111,6 +131,11 @@ export interface LoginResponse {
   tokens: AuthTokens;
 }
 
+export interface RegisterRequest {
+  username: string;
+  password: string;
+}
+
 export interface PaginatedResponse<T> {
   items: T[];
   total: number;
@@ -136,3 +161,26 @@ export interface ApiError {
   message: string;
   code?: string;
 }
+
+/** One AcoustID candidate from `GET /tracks/{id}/metadata/matches` (§A7). */
+export interface MetadataMatch {
+  acoustid: string;
+  /** Confidence 0..1. */
+  score: number;
+  recordingMbid?: string;
+  releaseGroupMbid?: string;
+  title?: string;
+  artist?: string;
+  album?: string;
+  year?: number;
+}
+
+/** Manual edits / an accepted match, sent to `PUT /tracks/{id}/metadata`. */
+export interface MetadataEdit {
+  title?: string;
+  artistName?: string;
+  albumTitle?: string;
+  year?: number;
+  genre?: string;
+  trackNumber?: number;
+}

src/components/common/ConnectionStatus.tsx

@@ -22,9 +22,15 @@ export function ConnectionStatus() {
   const status = useConnectionStatus();
   const baseUrl = getApiBaseUrl();
   const label = t(STATUS_KEY[status]);
+  // When the backend is unreachable the UI falls back to the persisted RTKQ
+  // cache (Tier 2), so flag that the data on screen is last-seen, not live.
+  const offline = status === 'disconnected' || status === 'error';
+  const tip = offline
+    ? `${label} · ${baseUrl} · ${t('conn.cached')}`
+    : `${label} · ${baseUrl}`;
 
   return (
-    <Tooltip content={`${label} · ${baseUrl}`}>
+    <Tooltip content={tip}>
       <Badge variant={STATUS_VARIANTS[status]} dot>
         {label}
       </Badge>

src/components/common/Icon.tsx

@@ -19,6 +19,7 @@ import {
   GearSix,
   HardDrives,
   Heart,
+  Info,
   MagnifyingGlass,
   Pause,
   Play,
@@ -69,6 +70,7 @@ const ICONS = {
   'skip-forward': SkipForward,
   repeat: Repeat,
   heart: Heart,
+  info: Info,
   'thumbs-down': ThumbsDown,
   'speaker-high': SpeakerHigh,
   'speaker-x': SpeakerSimpleX,

src/components/layout/AppShell.tsx

@@ -3,6 +3,7 @@ import { Suspense } from 'react';
 import { Sidebar } from './Sidebar';
 import { PersistentPlayer } from '../player/PersistentPlayer';
 import { QueuePanel } from '../player/QueuePanel';
+import { TrackInfoDrawer } from '../track/TrackInfoDrawer';
 import { LoadingSkeleton } from '../common/LoadingSkeleton';
 
 export function AppShell() {
@@ -31,6 +32,7 @@ export function AppShell() {
           </div>
         </main>
         <QueuePanel />
+        <TrackInfoDrawer />
       </div>
       <PersistentPlayer />
     </div>

src/components/player/PersistentPlayer.tsx

@@ -10,12 +10,14 @@ import {
   setVolume,
   toggleShuffle,
   setRepeat,
-  toggleNowPlaying,
   toggleQueue,
 } from '../../store/slices/player';
+import { openTrackInfo } from '../../store/slices/ui';
 import { useAudioPlayer } from '../../hooks/useAudioPlayer';
+import { useStreamCached } from '../../hooks/useStreamCached';
+import { useResolvedQueueEntry } from '../../hooks/useResolvedQueueEntry';
 import { formatDuration } from '../../lib/format';
-import { getCoverUrl } from '../../api/endpoints/streaming';
+import { getCoverUrl, getTrackCoverUrl } from '../../api/endpoints/streaming';
 
 export function PersistentPlayer() {
   const { t } = useTranslation();
@@ -23,27 +25,40 @@ export function PersistentPlayer() {
   const { seek, playNext, playPrev } = useAudioPlayer();
   const player = useAppSelector((s) => s.player);
   const queue = useAppSelector((s) => s.queue);
+  const token = useAppSelector((s) => s.auth.accessToken);
   const currentEntry = queue.entries[queue.currentIndex];
+  // Read through to the live Track cache so enrichment updates reach the player,
+  // not just the play-time snapshot frozen in the queue slice.
+  const current = useResolvedQueueEntry(currentEntry);
+  // Source indicator: cached → playing locally, otherwise streaming.
+  const cached = useStreamCached(currentEntry?.trackId);
 
   if (!currentEntry && !player.currentTrackId) {
     return <div className="player empty">{t('player.nothingPlaying')}</div>;
   }
 
-  const artUrl = getCoverUrl(currentEntry?.albumArtUrl);
+  const artUrl =
-  const seedLabel = currentEntry?.albumTitle ?? currentEntry?.title ?? '';
+    getCoverUrl(currentEntry?.albumArtUrl) ??
-  const onStream = true;
+    (token && current?.hasCover
+      ? getTrackCoverUrl(current.trackId, token, true)
+      : undefined);
+  const seedLabel = current?.albumTitle ?? current?.title ?? '';
+  const onStream = !cached;
 
   return (
     <div className="player">
       <div
         className="pl-now"
-        onClick={() => dispatch(toggleNowPlaying())}
+        onClick={() =>
-        style={{ cursor: 'pointer' }}
+          currentEntry && dispatch(openTrackInfo(currentEntry.trackId))
+        }
+        style={{ cursor: currentEntry ? 'pointer' : 'default' }}
+        title={currentEntry ? t('trackInfo.open') : undefined}
       >
         <ArtTile seed={seedLabel} size={54} label={seedLabel} src={artUrl} />
         <div className="pl-now-tt">
-          <div className="t">{currentEntry?.title ?? '—'}</div>
+          <div className="t">{current?.title ?? '—'}</div>
-          <div className="a">{currentEntry?.artistName ?? ''}</div>
+          <div className="a">{current?.artistName ?? ''}</div>
           <div
             className="pl-srcbadge"
             style={{ color: onStream ? 'var(--fg-3)' : 'var(--lime)' }}

src/components/player/QueuePanel.tsx

@@ -7,8 +7,11 @@ import {
   goToIndex,
   removeFromQueue,
   clearQueue,
+  type QueueEntry,
 } from '../../store/slices/queue';
 import { toggleQueue } from '../../store/slices/player';
+import { openTrackInfo } from '../../store/slices/ui';
+import { useResolvedQueueEntry } from '../../hooks/useResolvedQueueEntry';
 
 export function QueuePanel() {
   const { t } = useTranslation();
@@ -16,8 +19,9 @@ export function QueuePanel() {
   const queue = useAppSelector((s) => s.queue);
   const isOpen = useAppSelector((s) => s.player.isQueueOpen);
 
-  const now =
+  const nowEntry =
     queue.currentIndex >= 0 ? queue.entries[queue.currentIndex] : undefined;
+  const now = useResolvedQueueEntry(nowEntry);
   const upNext = queue.entries
     .map((entry, index) => ({ entry, index }))
     .filter(({ index }) => index > queue.currentIndex);
@@ -82,14 +86,27 @@ export function QueuePanel() {
                   <div className="t">{now.title}</div>
                   <div className="r">{now.artistName}</div>
                 </div>
-                <Icon name="cloud" style={{ color: 'var(--fg-3)' }} />
+                <button
+                  type="button"
+                  className="iconbtn sm"
+                  onClick={() => dispatch(openTrackInfo(now.trackId))}
+                  title={t('trackInfo.open')}
+                >
+                  <Icon name="info" />
+                </button>
               </div>
 
               {isRadio && (
                 <div className="qd-radio">
                   <div className="row">
                     <Icon name="radio" />
-                    <span style={{ fontSize: 13, fontWeight: 600, color: 'var(--fg-1)' }}>
+                    <span
+                      style={{
+                        fontSize: 13,
+                        fontWeight: 600,
+                        color: 'var(--fg-1)',
+                      }}
+                    >
                       {t('queue.radioActive')}
                     </span>
                     <div style={{ flex: 1 }} />
@@ -120,33 +137,12 @@ export function QueuePanel() {
                 <div className="qd-empty">{t('queue.nothingNext')}</div>
               ) : (
                 upNext.map(({ entry, index }) => (
-                  <div
+                  <QueueRow
                     key={`${entry.trackId}-${index}`}
-                    className="qrow"
+                    entry={entry}
-                    onDoubleClick={() => dispatch(goToIndex(index))}
+                    onPlay={() => dispatch(goToIndex(index))}
-                    title={t('queue.doubleClickPlay')}
+                    onRemove={() => dispatch(removeFromQueue(index))}
-                  >
+                  />
-                    <span className="grip">
-                      <Icon name="dots-six-vertical" />
-                    </span>
-                    <ArtTile
-                      seed={entry.albumTitle}
-                      size={36}
-                      label={entry.albumTitle}
-                    />
-                    <div className="qt">
-                      <div className="t">{entry.title}</div>
-                      <div className="r">{entry.artistName}</div>
-                    </div>
-                    <button
-                      type="button"
-                      className="iconbtn sm"
-                      onClick={() => dispatch(removeFromQueue(index))}
-                      title={t('queue.removeFromQueue')}
-                    >
-                      <Icon name="x" />
-                    </button>
-                  </div>
                 ))
               )}
 
@@ -162,3 +158,44 @@ export function QueuePanel() {
     </aside>
   );
 }
+
+/** An "up next" row, resolving its display fields against the live Track cache
+ * (same read-through as the now-playing entry) so enrichment updates show. */
+function QueueRow({
+  entry,
+  onPlay,
+  onRemove,
+}: {
+  entry: QueueEntry;
+  onPlay: () => void;
+  onRemove: () => void;
+}) {
+  const { t } = useTranslation();
+  const resolved = useResolvedQueueEntry(entry);
+  const albumTitle = resolved?.albumTitle ?? entry.albumTitle;
+
+  return (
+    <div
+      className="qrow"
+      onDoubleClick={onPlay}
+      title={t('queue.doubleClickPlay')}
+    >
+      <span className="grip">
+        <Icon name="dots-six-vertical" />
+      </span>
+      <ArtTile seed={albumTitle} size={36} label={albumTitle} />
+      <div className="qt">
+        <div className="t">{resolved?.title ?? entry.title}</div>
+        <div className="r">{resolved?.artistName ?? entry.artistName}</div>
+      </div>
+      <button
+        type="button"
+        className="iconbtn sm"
+        onClick={onRemove}
+        title={t('queue.removeFromQueue')}
+      >
+        <Icon name="x" />
+      </button>
+    </div>
+  );
+}

src/components/track/MetadataStatusBadge.tsx

@@ -0,0 +1,47 @@
+import { Badge, Spinner, Tooltip } from '@olly/modern-sk';
+import { useTranslation } from 'react-i18next';
+import type { MetadataStatus } from '../../api/types';
+
+interface Props {
+  status: MetadataStatus;
+  /** Reason shown in the tooltip for a `failed` status. */
+  error?: string;
+  /** When true, render nothing for the normal `enriched` state (keeps dense
+   * track lists quiet; the upload screen sets this false to confirm success). */
+  hideWhenEnriched?: boolean;
+}
+
+type Variant = 'lime' | 'ember' | 'neutral' | 'outline';
+
+const VARIANT: Record<MetadataStatus, Variant> = {
+  pending: 'neutral',
+  enriched: 'lime',
+  failed: 'ember',
+  manual: 'outline',
+};
+
+/**
+ * Shows a track's metadata-enrichment state (distinct from file availability).
+ * `pending` carries a spinner; `failed` exposes the backend reason on hover.
+ */
+export function MetadataStatusBadge({
+  status,
+  error,
+  hideWhenEnriched = true,
+}: Props) {
+  const { t } = useTranslation();
+  if (status === 'enriched' && hideWhenEnriched) return null;
+
+  const label = t(`metadata.status.${status}`);
+  const tooltip =
+    status === 'failed' && error ? error : t(`metadata.statusHint.${status}`);
+
+  return (
+    <Tooltip content={tooltip}>
+      <Badge variant={VARIANT[status]} dot={status !== 'pending'}>
+        {status === 'pending' ? <Spinner size="sm" /> : null}
+        {label}
+      </Badge>
+    </Tooltip>
+  );
+}

src/components/track/TrackContextMenu.tsx

@@ -10,6 +10,7 @@ import { useTranslation } from 'react-i18next';
 import { useAppDispatch } from '../../hooks/useAppDispatch';
 import { addToQueue, addNextInQueue } from '../../store/slices/queue';
 import { play } from '../../store/slices/player';
+import { openTrackInfo } from '../../store/slices/ui';
 import type { Track } from '../../api/types';
 
 interface Props {
@@ -42,21 +43,45 @@ export function TrackContextMenu({
   return (
     <Menu>
       <MenuTrigger asChild>
-        <IconButton variant="ghost" size="sm" aria-label={t('track.menu.options')}>
+        <IconButton
+          variant="ghost"
+          size="sm"
+          aria-label={t('track.menu.options')}
+        >
           ⋯
         </IconButton>
       </MenuTrigger>
       <MenuContent>
-        <MenuItem onSelect={() => { dispatch(play(track.id)); }}>
+        <MenuItem
+          onSelect={() => {
+            dispatch(play(track.id));
+          }}
+        >
           {t('track.menu.playNow')}
         </MenuItem>
-        <MenuItem onSelect={() => { dispatch(addNextInQueue(entry)); }}>
+        <MenuItem
+          onSelect={() => {
+            dispatch(addNextInQueue(entry));
+          }}
+        >
           {t('track.menu.playNext')}
         </MenuItem>
-        <MenuItem onSelect={() => { dispatch(addToQueue(entry)); }}>
+        <MenuItem
+          onSelect={() => {
+            dispatch(addToQueue(entry));
+          }}
+        >
           {t('track.menu.addToQueue')}
         </MenuItem>
         <MenuSeparator />
+        <MenuItem
+          onSelect={() => {
+            dispatch(openTrackInfo(track.id));
+          }}
+        >
+          {t('track.menu.info')}
+        </MenuItem>
+        <MenuSeparator />
         {onAddToPlaylist && (
           <MenuItem onSelect={() => onAddToPlaylist(track)}>
             {t('track.menu.addToPlaylist')}

src/components/track/TrackInfoDrawer.tsx

@@ -0,0 +1,319 @@
+import type { ReactNode } from 'react';
+import { Badge, Button } from '@olly/modern-sk';
+import { useTranslation } from 'react-i18next';
+import { Link, useNavigate } from 'react-router';
+import { skipToken } from '@reduxjs/toolkit/query';
+import { Icon } from '../common/Icon';
+import { ArtTile } from '../common/ArtTile';
+import { AvailabilityBadge } from './AvailabilityBadge';
+import { MetadataStatusBadge } from './MetadataStatusBadge';
+import { LoadingSkeleton } from '../common/LoadingSkeleton';
+import { ErrorState } from '../common/ErrorState';
+import { EmptyState } from '../common/EmptyState';
+import { useAppDispatch, useAppSelector } from '../../hooks/useAppDispatch';
+import { closeTrackInfo } from '../../store/slices/ui';
+import { play } from '../../store/slices/player';
+import { addToQueue } from '../../store/slices/queue';
+import {
+  useGetTrackQuery,
+  useGetAlbumQuery,
+} from '../../api/endpoints/library';
+import { getTrackCoverUrl } from '../../api/endpoints/streaming';
+import {
+  formatDuration,
+  formatFileSize,
+  formatDateTime,
+} from '../../lib/format';
+import type { Track } from '../../api/types';
+
+/**
+ * Right-side "Get Info"-style drawer for a single track. Rendered after the
+ * QueuePanel in AppShell so it sits to the *right* of the queue when both are
+ * open. Open state lives in `ui.trackInfoId`; it reads the live Track (and its
+ * album) from the RTKQ cache so enrichment updates stay in sync.
+ */
+export function TrackInfoDrawer() {
+  const trackId = useAppSelector((s) => s.ui.trackInfoId);
+  const isOpen = trackId !== null;
+
+  return (
+    <aside className={`tid${isOpen ? '' : ' closed'}`} aria-hidden={!isOpen}>
+      <div className="tid-inner">
+        {trackId ? <TrackInfoContent trackId={trackId} /> : null}
+      </div>
+    </aside>
+  );
+}
+
+function TrackInfoContent({ trackId }: { trackId: string }) {
+  const { t } = useTranslation();
+  const dispatch = useAppDispatch();
+  const navigate = useNavigate();
+  const token = useAppSelector((s) => s.auth.accessToken);
+
+  const {
+    data: track,
+    isLoading,
+    isError,
+    refetch,
+  } = useGetTrackQuery(trackId);
+  // Album record fills in fields the lean TrackOut omits (year especially).
+  const { data: album } = useGetAlbumQuery(track?.albumId ?? skipToken);
+
+  const close = () => dispatch(closeTrackInfo());
+
+  return (
+    <>
+      <div className="tid-head">
+        <h3>{t('trackInfo.title')}</h3>
+        <div style={{ flex: 1 }} />
+        <button
+          type="button"
+          className="iconbtn sm"
+          onClick={close}
+          title={t('trackInfo.close')}
+        >
+          <Icon name="x" />
+        </button>
+      </div>
+
+      <div className="tid-scroll">
+        {isLoading ? (
+          <LoadingSkeleton rows={6} />
+        ) : isError ? (
+          <ErrorState onRetry={refetch} />
+        ) : !track ? (
+          <EmptyState title={t('trackInfo.notFound')} />
+        ) : (
+          <TrackInfoBody
+            track={track}
+            albumYear={album?.year}
+            albumTrackCount={album?.trackCount}
+            coverUrl={
+              token
+                ? getTrackCoverUrl(track.id, token, track.hasCover)
+                : undefined
+            }
+            onPlay={() => dispatch(play(track.id))}
+            onQueue={() =>
+              dispatch(
+                addToQueue({
+                  trackId: track.id,
+                  title: track.title,
+                  artistName: track.artistName,
+                  albumTitle: track.albumTitle,
+                  durationMs: track.durationMs,
+                  albumArtUrl: track.albumArtUrl,
+                }),
+              )
+            }
+            onEdit={() => {
+              navigate(`/tracks/${track.id}/metadata`);
+            }}
+          />
+        )}
+      </div>
+    </>
+  );
+}
+
+function TrackInfoBody({
+  track,
+  albumYear,
+  albumTrackCount,
+  coverUrl,
+  onPlay,
+  onQueue,
+  onEdit,
+}: {
+  track: Track;
+  albumYear?: number;
+  albumTrackCount?: number;
+  coverUrl?: string;
+  onPlay: () => void;
+  onQueue: () => void;
+  onEdit: () => void;
+}) {
+  const { t } = useTranslation();
+  const seedLabel = track.albumTitle || track.title;
+  const year = track.year ?? albumYear;
+
+  return (
+    <>
+      <div className="tid-cover">
+        {coverUrl ? (
+          <img src={coverUrl} alt={track.albumTitle} />
+        ) : (
+          <ArtTile seed={seedLabel} size={256} label={seedLabel} radius={12} />
+        )}
+      </div>
+
+      <h2 className="tid-title">{track.title}</h2>
+      <Link className="tid-sub" to={`/artists/${track.artistId}`}>
+        {track.artistName}
+      </Link>
+      {track.albumId && (
+        <Link className="tid-sub tid-album" to={`/albums/${track.albumId}`}>
+          <Icon name="vinyl-record" />
+          {track.albumTitle}
+        </Link>
+      )}
+
+      <div className="tid-actions">
+        <Button variant="primary" size="sm" onClick={onPlay}>
+          <Icon name="play" fill /> {t('trackInfo.play')}
+        </Button>
+        <Button variant="ghost" size="sm" onClick={onQueue}>
+          <Icon name="queue" /> {t('trackInfo.addToQueue')}
+        </Button>
+        <Button variant="ghost" size="sm" onClick={onEdit}>
+          {t('trackInfo.editMetadata')}
+        </Button>
+      </div>
+
+      <InfoSection title={t('trackInfo.sections.status')}>
+        <div className="tid-status">
+          <AvailabilityBadge availability={track.availability} />
+          <MetadataStatusBadge
+            status={track.metadataStatus}
+            error={track.metadataError}
+            hideWhenEnriched={false}
+          />
+          {track.liked && (
+            <Badge variant="lime" dot>
+              {t('trackInfo.liked')}
+            </Badge>
+          )}
+        </div>
+        {track.metadataStatus === 'failed' && track.metadataError && (
+          <p className="tid-error">{track.metadataError}</p>
+        )}
+      </InfoSection>
+
+      <InfoSection title={t('trackInfo.sections.general')}>
+        <InfoRow
+          label={t('trackInfo.fields.artist')}
+          value={track.artistName}
+        />
+        <InfoRow
+          label={t('trackInfo.fields.album')}
+          value={track.albumTitle || undefined}
+        />
+        <InfoRow
+          label={t('trackInfo.fields.trackNumber')}
+          value={
+            track.trackNumber !== undefined
+              ? albumTrackCount
+                ? t('trackInfo.trackOf', {
+                    n: track.trackNumber,
+                    total: albumTrackCount,
+                  })
+                : String(track.trackNumber)
+              : undefined
+          }
+        />
+        <InfoRow
+          label={t('trackInfo.fields.disc')}
+          value={
+            track.discNumber !== undefined
+              ? String(track.discNumber)
+              : undefined
+          }
+        />
+        <InfoRow
+          label={t('trackInfo.fields.year')}
+          value={year !== undefined ? String(year) : undefined}
+        />
+        <InfoRow label={t('trackInfo.fields.genre')} value={track.genre} />
+        <InfoRow
+          label={t('trackInfo.fields.duration')}
+          value={formatDuration(track.durationMs)}
+        />
+      </InfoSection>
+
+      <InfoSection title={t('trackInfo.sections.file')}>
+        <InfoRow
+          label={t('trackInfo.fields.format')}
+          value={track.format?.toUpperCase()}
+        />
+        <InfoRow
+          label={t('trackInfo.fields.bitrate')}
+          value={
+            track.bitrate !== undefined
+              ? t('trackInfo.kbps', { n: track.bitrate })
+              : undefined
+          }
+        />
+        <InfoRow
+          label={t('trackInfo.fields.size')}
+          value={
+            track.fileSize !== undefined
+              ? formatFileSize(track.fileSize)
+              : undefined
+          }
+        />
+        <InfoRow
+          label={t('trackInfo.fields.source')}
+          value={track.source}
+          mono
+        />
+        <InfoRow
+          label={t('trackInfo.fields.added')}
+          value={formatDateTime(track.createdAt)}
+        />
+        <InfoRow
+          label={t('trackInfo.fields.enriched')}
+          value={formatDateTime(track.enrichedAt)}
+        />
+      </InfoSection>
+
+      <InfoSection title={t('trackInfo.sections.identifiers')}>
+        <InfoRow label={t('trackInfo.fields.trackId')} value={track.id} mono />
+        <InfoRow
+          label={t('trackInfo.fields.albumId')}
+          value={track.albumId || undefined}
+          mono
+        />
+        <InfoRow
+          label={t('trackInfo.fields.artistId')}
+          value={track.artistId}
+          mono
+        />
+      </InfoSection>
+    </>
+  );
+}
+
+function InfoSection({
+  title,
+  children,
+}: {
+  title: string;
+  children: ReactNode;
+}) {
+  return (
+    <section className="tid-section">
+      <span className="msk-label tid-section-label">{title}</span>
+      {children}
+    </section>
+  );
+}
+
+/** A label/value row; renders nothing when the value is empty (Finder-style). */
+function InfoRow({
+  label,
+  value,
+  mono,
+}: {
+  label: string;
+  value?: string;
+  mono?: boolean;
+}) {
+  if (!value) return null;
+  return (
+    <div className="tid-row">
+      <span className="tid-row-k">{label}</span>
+      <span className={`tid-row-v${mono ? ' mono' : ''}`}>{value}</span>
+    </div>
+  );
+}

src/components/track/TrackRow.tsx

@@ -1,11 +1,12 @@
 import { Row } from '@olly/modern-sk';
 import { TrackContextMenu } from './TrackContextMenu';
 import { AvailabilityBadge } from './AvailabilityBadge';
+import { MetadataStatusBadge } from './MetadataStatusBadge';
 import { formatDuration } from '../../lib/format';
 import { useAppDispatch, useAppSelector } from '../../hooks/useAppDispatch';
 import { play } from '../../store/slices/player';
 import type { Track } from '../../api/types';
-import { getCoverUrl } from '../../api/endpoints/streaming';
+import { getCoverUrl, getTrackCoverUrl } from '../../api/endpoints/streaming';
 
 interface Props {
   track: Track;
@@ -27,8 +28,13 @@ export function TrackRow({
   const dispatch = useAppDispatch();
   const currentTrackId = useAppSelector((s) => s.player.currentTrackId);
   const isPlaying = useAppSelector((s) => s.player.isPlaying);
+  const token = useAppSelector((s) => s.auth.accessToken);
   const isActive = currentTrackId === track.id;
-  const artUrl = getCoverUrl(track.albumArtUrl);
+  // Prefer an explicit album art URL; otherwise serve the track's own cover
+  // (needs the token in the query string — `<img>` can't send a header).
+  const artUrl =
+    getCoverUrl(track.albumArtUrl) ??
+    (token ? getTrackCoverUrl(track.id, token, track.hasCover) : undefined);
 
   return (
     <Row
@@ -95,7 +101,13 @@ export function TrackRow({
           {showAlbum && ` · ${track.albumTitle}`}
         </div>
       </div>
-      <AvailabilityBadge availability={track.availability} />
+      <div style={{ display: 'flex', alignItems: 'center', gap: '0.5rem' }}>
+        <MetadataStatusBadge
+          status={track.metadataStatus}
+          error={track.metadataError}
+        />
+        <AvailabilityBadge availability={track.availability} />
+      </div>
       <div style={{ display: 'flex', alignItems: 'center', gap: '0.5rem' }}>
         <span
           style={{

src/config/env.ts

@@ -1,2 +1,41 @@
+/**
+ * Default backend base URL — the operator-set fallback used when no specific
+ * instance is active. Resolution order:
+ *
+ *   1. window.__APP_CONFIG__.apiBaseUrl  — runtime, injected by the container
+ *      at start from $PUBLIC_API_BASE_URL (see public/config.js). Lets one
+ *      prebuilt image point at any backend origin without rebuilding.
+ *   2. import.meta.env.PUBLIC_API_BASE_URL — build-time default (rsbuild inlines
+ *      PUBLIC_* vars). Used in local dev and as a baked fallback.
+ *   3. '/api/v1' — same-origin relative path (works behind a reverse proxy).
+ *
+ * The user's chosen instance still wins over all of these — see
+ * runtime-config.ts / instances.ts.
+ */
+function runtimeApiBaseUrl(): string | undefined {
+  if (typeof window === 'undefined') return undefined;
+  const value = window.__APP_CONFIG__?.apiBaseUrl;
+  return value ? value : undefined;
+}
+
 export const DEFAULT_API_BASE_URL =
-  import.meta.env.PUBLIC_API_BASE_URL ?? '/api/v1';
+  runtimeApiBaseUrl() ?? import.meta.env.PUBLIC_API_BASE_URL ?? '/api/v1';
+
+/**
+ * Whether the public sign-up UI is shown. Same precedence as the base URL:
+ * runtime operator config (injected into `window.__APP_CONFIG__` at container
+ * start) wins over the build-time `PUBLIC_ENABLE_REGISTRATION` env, which
+ * defaults to enabled. This only gates the *UI*; the backend independently
+ * enforces `ALLOW_REGISTRATION` and is the real authority.
+ */
+function parseFlag(value: string | undefined): boolean | undefined {
+  if (value == null || value === '') return undefined;
+  return value !== 'false' && value !== '0';
+}
+
+export const REGISTRATION_ENABLED: boolean =
+  (typeof window !== 'undefined'
+    ? window.__APP_CONFIG__?.enableRegistration
+    : undefined) ??
+  parseFlag(import.meta.env.PUBLIC_ENABLE_REGISTRATION) ??
+  true;

src/config/instances.ts

@@ -29,8 +29,13 @@ const ACTIVE_KEY = 'mcma:activeInstance';
 const LEGACY_URL_KEY = 'mcma_api_base_url';
 const LEGACY_AUTH_KEY = 'mcma_auth';
 
+// The UI always talks to the `/api/v1` contract, so users only enter the
+// origin (and optional reverse-proxy prefix). We append the contract path
+// here, the single choke point for both the base URL and the instance id, so
+// `domain.com`, `domain.com/`, and `domain.com/api/v1` all converge.
 function normalizeUrl(url: string): string {
-  return url.trim().replace(/\/+$/, '');
+  const trimmed = url.trim().replace(/\/+$/, '');
+  return /\/api\/v1$/.test(trimmed) ? trimmed : `${trimmed}/api/v1`;
 }
 
 /** Stable, readable id from a base URL — also serves as the storage namespace. */
@@ -93,6 +98,11 @@ export function upsertInstance(url: string, name?: string): Instance {
   return inst;
 }
 
+/** Clear a backend's stored session without forgetting the instance itself. */
+export function clearInstanceAuth(id: string): void {
+  localStorage.removeItem(scopedKey('auth', id));
+}
+
 /** Remove a backend and wipe every scoped key it owns. */
 export function removeInstance(id: string): void {
   writeRegistry(readRegistry().filter((i) => i.id !== id));

src/env.d.ts

@@ -1,7 +1,17 @@
 /// <reference types="@rsbuild/core/types" />
 interface ImportMetaEnv {
   readonly PUBLIC_API_BASE_URL?: string;
+  readonly PUBLIC_ENABLE_REGISTRATION?: string;
 }
 interface ImportMeta {
   readonly env: ImportMetaEnv;
 }
+
+// Runtime operator config injected by /config.js before the app bundle loads
+// (written from $PUBLIC_API_BASE_URL at container start). See src/config/env.ts.
+interface Window {
+  __APP_CONFIG__?: {
+    apiBaseUrl?: string;
+    enableRegistration?: boolean;
+  };
+}

src/features/connect/ConnectPage.tsx

@@ -1,18 +1,191 @@
 import { useState } from 'react';
 import { useNavigate } from 'react-router';
 import { useTranslation } from 'react-i18next';
-import { Card, TextField, Button, Callout, Badge } from '@olly/modern-sk';
+import type { FetchBaseQueryError } from '@reduxjs/toolkit/query';
+import {
+  Card,
+  TextField,
+  Button,
+  Callout,
+  Badge,
+  Dialog,
+  IconButton,
+} from '@olly/modern-sk';
 import { Icon } from '../../components/common/Icon';
 import { useAppDispatch } from '../../hooks/useAppDispatch';
+import { useConnectionStatus } from '../../hooks/useConnectionStatus';
 import { setTokens, setUser } from '../../store/slices/auth';
-import { setApiBaseUrl } from '../../config/runtime-config';
+import {
+  useLoginMutation,
+  useRegisterMutation,
+} from '../../api/endpoints/auth';
+import { REGISTRATION_ENABLED } from '../../config/env';
 import {
   listInstances,
   getActiveInstanceId,
   setActiveInstanceId,
   removeInstance,
+  clearInstanceAuth,
+  upsertInstance,
+  type Instance,
 } from '../../config/instances';
-import type { User } from '../../api/types';
+
+type Mode = 'login' | 'register';
+
+const HEALTH_VARIANTS = {
+  connected: 'lime',
+  connecting: 'neutral',
+  disconnected: 'ember',
+  error: 'ember',
+} as const;
+
+const HEALTH_KEY = {
+  connected: 'conn.connected',
+  connecting: 'conn.connecting',
+  disconnected: 'conn.disconnected',
+  error: 'conn.error',
+} as const;
+
+/** Map an RTKQ login failure to a user-facing i18n key. */
+function resolveLoginError(err: unknown): string {
+  const e = err as FetchBaseQueryError | undefined;
+  if (e && 'status' in e) {
+    if (e.status === 'FETCH_ERROR') return 'connect.errors.unreachable';
+    if (e.status === 401) return 'connect.errors.badCredentials';
+  }
+  return 'connect.errors.generic';
+}
+
+/** Map an RTKQ register failure to a user-facing i18n key. */
+function resolveRegisterError(err: unknown): string {
+  const e = err as FetchBaseQueryError | undefined;
+  if (e && 'status' in e) {
+    if (e.status === 'FETCH_ERROR') return 'connect.errors.unreachable';
+    if (e.status === 409) return 'connect.errors.usernameTaken';
+    if (e.status === 422) return 'connect.errors.passwordTooShort';
+    if (e.status === 403) return 'connect.errors.registrationDisabled';
+  }
+  return 'connect.errors.registerFailed';
+}
+
+function InstanceRow({
+  inst,
+  selected,
+  onSelect,
+  onLogout,
+  onRemove,
+}: {
+  inst: Instance;
+  selected: boolean;
+  onSelect: () => void;
+  onLogout: () => void;
+  onRemove: () => void;
+}) {
+  const { t } = useTranslation();
+  const status = useConnectionStatus(inst.baseUrl);
+  const [dialogOpen, setDialogOpen] = useState(false);
+
+  return (
+    <div
+      style={{
+        display: 'flex',
+        alignItems: 'center',
+        gap: '0.625rem',
+        padding: '0.375rem 0',
+      }}
+    >
+      <Badge variant={HEALTH_VARIANTS[status]} dot>
+        {t(HEALTH_KEY[status])}
+      </Badge>
+      <div style={{ minWidth: 0, flex: 1 }}>
+        <div
+          style={{
+            fontSize: '0.875rem',
+            fontWeight: 600,
+            color: 'var(--color-text-1)',
+            overflow: 'hidden',
+            textOverflow: 'ellipsis',
+            whiteSpace: 'nowrap',
+          }}
+        >
+          {inst.name}
+        </div>
+        <div
+          style={{
+            fontSize: '0.75rem',
+            color: 'var(--color-text-3)',
+            overflow: 'hidden',
+            textOverflow: 'ellipsis',
+            whiteSpace: 'nowrap',
+          }}
+        >
+          {inst.baseUrl}
+        </div>
+      </div>
+      {selected ? (
+        <Badge variant="outline">{t('connect.domains.selected')}</Badge>
+      ) : (
+        <Button variant="ghost" size="sm" onClick={onSelect}>
+          {t('connect.domains.use')}
+        </Button>
+      )}
+      <Dialog
+        open={dialogOpen}
+        onOpenChange={setDialogOpen}
+        title={t('connect.removeDialog.title')}
+        description={t('connect.removeDialog.description', {
+          name: inst.name,
+        })}
+        trigger={
+          <button
+            type="button"
+            className="iconbtn sm"
+            title={t('connect.domains.forgetTitle')}
+          >
+            <Icon name="trash" />
+          </button>
+        }
+        footer={
+          <div
+            style={{
+              display: 'flex',
+              justifyContent: 'flex-end',
+              gap: '0.5rem',
+            }}
+          >
+            <Button
+              variant="ghost"
+              size="sm"
+              onClick={() => setDialogOpen(false)}
+            >
+              {t('connect.removeDialog.cancel')}
+            </Button>
+            <Button
+              variant="ghost"
+              size="sm"
+              onClick={() => {
+                setDialogOpen(false);
+                onLogout();
+              }}
+            >
+              {t('connect.removeDialog.logout')}
+            </Button>
+            <Button
+              variant="ember"
+              size="sm"
+              onClick={() => {
+                setDialogOpen(false);
+                onRemove();
+              }}
+            >
+              {t('connect.removeDialog.removeAndLogout')}
+            </Button>
+          </div>
+        }
+      />
+    </div>
+  );
+}
 
 export function ConnectPage() {
   const { t } = useTranslation();
@@ -21,41 +194,80 @@ export function ConnectPage() {
 
   const [rev, setRev] = useState(0);
   const instances = listInstances();
-  const activeId = getActiveInstanceId();
 
-  const [apiUrl, setApiUrl] = useState('https://');
+  const [selectedId, setSelectedId] = useState<string | null>(() =>
+    getActiveInstanceId(),
+  );
+  const selectedInstance = instances.find((i) => i.id === selectedId) ?? null;
+  const [instanceAddShown, setInstanceAddShown] = useState(false);
+
+  const [addUrl, setAddUrl] = useState('');
+
+  const [mode, setMode] = useState<Mode>('login');
   const [username, setUsername] = useState('');
   const [password, setPassword] = useState('');
+  const [error, setError] = useState<string | null>(null);
 
-  const switchTo = (id: string) => {
+  const [login, { isLoading: isLoggingIn }] = useLoginMutation();
+  const [register, { isLoading: isRegistering }] = useRegisterMutation();
+  const isLoading = isLoggingIn || isRegistering;
+
+  const switchMode = (next: Mode) => {
+    setMode(next);
+    setError(null);
+  };
+
+  // Switching the active instance and reloading lets the app pick the saved
+  // session for that instance back up (if any); if it has none, ProtectedRoute
+  // bounces back here and `selectedId` defaults to it, surfacing the login card.
+  const selectInstance = (id: string) => {
     setActiveInstanceId(id);
     window.location.assign('/');
   };
 
-  const forget = (id: string) => {
+  const handleAdd = (e: React.FormEvent) => {
-    removeInstance(id);
+    e.preventDefault();
+    const url = addUrl.trim();
+    if (!url || url === 'https://') return;
+    const inst = upsertInstance(url);
+    setActiveInstanceId(inst.id);
+    setAddUrl('https://');
+    setSelectedId(inst.id);
     setRev((r) => r + 1);
   };
 
-  const handleSubmit = (e: React.FormEvent) => {
+  const handleLogout = (id: string) => {
-    e.preventDefault();
+    clearInstanceAuth(id);
-    setApiBaseUrl(apiUrl);
+    setRev((r) => r + 1);
+  };
 
-    const fakeUser: User = {
+  const handleRemove = (id: string) => {
-      id: 'dev-user',
+    removeInstance(id);
-      username: username || 'dev',
+    if (selectedId === id) setSelectedId(getActiveInstanceId());
-      role: 'admin',
+    setRev((r) => r + 1);
-      createdAt: new Date().toISOString(),
+  };
-    };
+
-    dispatch(
+  const handleSubmit = async (e: React.FormEvent) => {
-      setTokens({
+    e.preventDefault();
-        accessToken: 'dev-token',
+    if (!selectedInstance) return;
-        refreshToken: 'dev-refresh',
+    setError(null);
-        expiresIn: 3600,
+
-      }),
+    try {
-    );
+      const action =
-    dispatch(setUser(fakeUser));
+        mode === 'register'
-    void navigate('/');
+          ? register({ username, password })
+          : login({ username, password });
+      const { user, tokens } = await action.unwrap();
+      dispatch(setTokens(tokens));
+      dispatch(setUser(user));
+      void navigate('/');
+    } catch (err) {
+      setError(
+        mode === 'register'
+          ? resolveRegisterError(err)
+          : resolveLoginError(err),
+      );
+    }
   };
 
   const labelStyle: React.CSSProperties = {
@@ -100,145 +312,172 @@ export function ConnectPage() {
           <Icon name="vinyl-record" fill /> MCMA
         </h1>
 
-        {instances.length > 0 && (
-          <Card>
-            <div
-              style={{
-                padding: '1.25rem 1.5rem',
-                display: 'flex',
-                flexDirection: 'column',
-                gap: '0.5rem',
-              }}
-            >
-              <span className="msk-label" style={{ marginBottom: '0.25rem' }}>
-                {t('connect.savedInstances')}
-              </span>
-              {instances.map((inst) => (
-                <div
-                  key={inst.id}
-                  style={{
-                    display: 'flex',
-                    alignItems: 'center',
-                    gap: '0.625rem',
-                    padding: '0.375rem 0',
-                  }}
-                >
-                  <span
-                    className={`led ${inst.id === activeId ? 'online' : 'offline'}`}
-                    style={{
-                      width: 8,
-                      height: 8,
-                      borderRadius: '50%',
-                      background:
-                        inst.id === activeId ? 'var(--lime)' : 'var(--fg-3)',
-                      boxShadow:
-                        inst.id === activeId ? '0 0 6px var(--lime)' : 'none',
-                      flexShrink: 0,
-                    }}
-                  />
-                  <div style={{ minWidth: 0, flex: 1 }}>
-                    <div
-                      style={{
-                        fontSize: '0.875rem',
-                        fontWeight: 600,
-                        color: 'var(--color-text-1)',
-                        overflow: 'hidden',
-                        textOverflow: 'ellipsis',
-                        whiteSpace: 'nowrap',
-                      }}
-                    >
-                      {inst.name}
-                    </div>
-                    <div
-                      style={{
-                        fontSize: '0.75rem',
-                        color: 'var(--color-text-3)',
-                        overflow: 'hidden',
-                        textOverflow: 'ellipsis',
-                        whiteSpace: 'nowrap',
-                      }}
-                    >
-                      {inst.baseUrl}
-                    </div>
-                  </div>
-                  {inst.id === activeId ? (
-                    <Badge variant="lime">{t('connect.active')}</Badge>
-                  ) : (
-                    <Button
-                      variant="ghost"
-                      size="sm"
-                      onClick={() => switchTo(inst.id)}
-                    >
-                      {t('connect.use')}
-                    </Button>
-                  )}
-                  <button
-                    type="button"
-                    className="iconbtn sm"
-                    onClick={() => forget(inst.id)}
-                    title={t('connect.forgetTitle')}
-                  >
-                    <Icon name="trash" />
-                  </button>
-                </div>
-              ))}
-            </div>
-          </Card>
-        )}
-
         <Card>
-          <form
+          <div
-            onSubmit={handleSubmit}
             style={{
+              padding: '1.25rem 1.5rem',
               display: 'flex',
               flexDirection: 'column',
-              gap: '1rem',
+              gap: '0.5rem',
-              padding: '1.5rem',
             }}
           >
-            <span className="msk-label">{t('connect.form.title')}</span>
+            {instances.length > 0 && (
-            <div>
+              <>
-              <label style={labelStyle}>{t('connect.form.serverUrl')}</label>
+                <span className="msk-label" style={{ marginBottom: '0.25rem' }}>
-              <TextField
+                  {t('connect.domains.title')}
-                value={apiUrl}
+                </span>
-                onChange={(e) => setApiUrl(e.target.value)}
+                {instances.map((inst) => (
-                placeholder="https://your-server.example.com/api/v1"
+                  <InstanceRow
-                required
+                    key={inst.id}
-              />
+                    inst={inst}
-            </div>
+                    selected={inst.id === selectedId}
-            <div>
+                    onSelect={() => selectInstance(inst.id)}
-              <label style={labelStyle}>{t('connect.form.username')}</label>
+                    onLogout={() => handleLogout(inst.id)}
-              <TextField
+                    onRemove={() => handleRemove(inst.id)}
-                value={username}
+                  />
-                onChange={(e) => setUsername(e.target.value)}
+                ))}
-                placeholder="username"
+              </>
-                autoComplete="username"
+            )}
-                required
+            <form
-              />
+              onSubmit={handleAdd}
-            </div>
+              style={{
-            <div>
+                display: 'flex',
-              <label style={labelStyle}>{t('connect.form.password')}</label>
+                gap: '0.5rem',
-              <TextField
+                marginTop: instances.length > 0 ? '0.5rem' : 0,
-                type="password"
+              }}
-                value={password}
-                onChange={(e) => setPassword(e.target.value)}
-                placeholder="password"
-                autoComplete="current-password"
-                required
-              />
-            </div>
-            <Callout variant="warning">
-              {t('connect.form.stubNote')}
-            </Callout>
-            <Button
-              type="submit"
-              variant="primary"
-              style={{ marginTop: '0.5rem' }}
             >
-              {t('connect.form.submit')}
+              {instanceAddShown ? (
-            </Button>
+                <>
-          </form>
+                  <TextField
+                    value={addUrl}
+                    onChange={(e) => setAddUrl(e.target.value)}
+                    placeholder={t('connect.domains.addPlaceholder')}
+                    style={{ flex: 1 }}
+                  />
+                  <IconButton type="submit" variant="primary">
+                    <Icon name="plus" />
+                  </IconButton>
+                </>
+              ) : (
+                <Button
+                  onClick={() => setInstanceAddShown(true)}
+                  style={{ width: '100%' }}
+                  variant="ghost"
+                >
+                  <Icon name="plus" /> {t('connect.domains.addButton')}
+                </Button>
+              )}
+            </form>
+          </div>
         </Card>
+
+        {selectedInstance && (
+          <Card>
+            <form
+              onSubmit={handleSubmit}
+              style={{
+                display: 'flex',
+                flexDirection: 'column',
+                gap: '1rem',
+                padding: '1.5rem',
+              }}
+            >
+              <span className="msk-label">
+                {mode === 'register'
+                  ? t('connect.login.registerTitle', {
+                      name: selectedInstance.name,
+                    })
+                  : t('connect.login.title', { name: selectedInstance.name })}
+              </span>
+              <div>
+                <label style={labelStyle}>{t('connect.login.username')}</label>
+                <TextField
+                  value={username}
+                  onChange={(e) => setUsername(e.target.value)}
+                  placeholder="username"
+                  autoComplete="username"
+                  required
+                />
+              </div>
+              <div>
+                <label style={labelStyle}>{t('connect.login.password')}</label>
+                <TextField
+                  type="password"
+                  value={password}
+                  onChange={(e) => setPassword(e.target.value)}
+                  placeholder="password"
+                  autoComplete={
+                    mode === 'register' ? 'new-password' : 'current-password'
+                  }
+                  required
+                />
+                {mode === 'register' && (
+                  <span
+                    style={{
+                      display: 'block',
+                      fontSize: '0.75rem',
+                      color: 'var(--color-text-3)',
+                      marginTop: '0.375rem',
+                    }}
+                  >
+                    {t('connect.login.passwordHint')}
+                  </span>
+                )}
+              </div>
+              {error && <Callout variant="danger">{t(error)}</Callout>}
+              <Button
+                type="submit"
+                variant="primary"
+                disabled={isLoading}
+                style={{ marginTop: '0.5rem' }}
+              >
+                {isLoading
+                  ? mode === 'register'
+                    ? t('connect.login.registering')
+                    : t('connect.login.submitting')
+                  : mode === 'register'
+                    ? t('connect.login.registerSubmit')
+                    : t('connect.login.submit')}
+              </Button>
+
+              {REGISTRATION_ENABLED && (
+                <div
+                  style={{
+                    textAlign: 'center',
+                    fontSize: '0.8125rem',
+                    color: 'var(--color-text-3)',
+                  }}
+                >
+                  {mode === 'register' ? (
+                    <>
+                      {t('connect.login.haveAccount')}{' '}
+                      <Button
+                        type="button"
+                        variant="ghost"
+                        size="sm"
+                        onClick={() => switchMode('login')}
+                      >
+                        {t('connect.login.signInLink')}
+                      </Button>
+                    </>
+                  ) : (
+                    <>
+                      {t('connect.login.noAccount')}{' '}
+                      <Button
+                        type="button"
+                        variant="ghost"
+                        size="sm"
+                        onClick={() => switchMode('register')}
+                      >
+                        {t('connect.login.registerLink')}
+                      </Button>
+                    </>
+                  )}
+                </div>
+              )}
+            </form>
+          </Card>
+        )}
       </div>
     </div>
   );

src/features/metadata-editor/MetadataEditorPage.tsx

@@ -1,4 +1,16 @@
+import { useEffect, useState } from 'react';
+import { useParams, useNavigate } from 'react-router';
 import { useTranslation } from 'react-i18next';
+import { Badge, Button, Callout, Card, IconButton, ScrollArea, Spinner, TextField } from '@olly/modern-sk';
+import {
+  useApplyMetadataMutation,
+  useEnrichTrackMutation,
+  useGetTrackQuery,
+  useLazyGetMetadataMatchesQuery,
+} from '../../api/endpoints/library';
+import type { MetadataMatch } from '../../api/types';
+import { LoadingSkeleton } from '../../components/common/LoadingSkeleton';
+import { ErrorState } from '../../components/common/ErrorState';
 import { Placeholder } from '../../components/common/Placeholder';
 
 interface Props {
@@ -6,13 +18,500 @@ interface Props {
   batch?: boolean;
 }
 
+/** Editable fields, kept as strings while in the form — parsed on save. */
+interface FormState {
+  title: string;
+  artistName: string;
+  albumTitle: string;
+  year: string;
+  genre: string;
+  trackNumber: string;
+}
+
+const EMPTY_FORM: FormState = {
+  title: '',
+  artistName: '',
+  albumTitle: '',
+  year: '',
+  genre: '',
+  trackNumber: '',
+};
+
+const labelStyle: React.CSSProperties = {
+  display: 'block',
+  fontSize: '0.8125rem',
+  fontWeight: 500,
+  marginBottom: '0.375rem',
+  color: 'var(--color-text-2)',
+};
+
+function fieldStyle(): React.CSSProperties {
+  return { width: '100%' };
+}
+
 /**
- * `/tracks/:trackId/metadata` (single) and `/metadata/batch` (bulk) — A7
+ * `/tracks/:trackId/metadata` — A7 metadata editor: manual edits + AcoustID
- * metadata editor with auto-enrichment / diff view. Scaffold only.
+ * match picker with a current-vs-proposed diff. `/metadata/batch` is deferred.
  */
 export function MetadataEditorPage({ batch = false }: Props) {
   const { t } = useTranslation();
+
+  if (batch) {
+    return <Placeholder title={t('pages.metadataBatch')} />;
+  }
+
+  return <SingleTrackEditor />;
+}
+
+function SingleTrackEditor() {
+  const { t } = useTranslation();
+  const navigate = useNavigate();
+  const { trackId } = useParams<{ trackId: string }>();
+
+  const trackQuery = useGetTrackQuery(trackId ?? '', { skip: !trackId });
+  const [findMatches, matchesResult] = useLazyGetMetadataMatchesQuery();
+  const [applyMetadata, applyResult] = useApplyMetadataMutation();
+  const [enrichTrack, enrichResult] = useEnrichTrackMutation();
+
+  const [form, setForm] = useState<FormState>(EMPTY_FORM);
+  const [initialized, setInitialized] = useState(false);
+  const [selectedMatch, setSelectedMatch] = useState<MetadataMatch | null>(null);
+
+  // Seed the form from the loaded track exactly once — afterwards it's the
+  // user's edit buffer and shouldn't be clobbered by refetches.
+  useEffect(() => {
+    if (initialized || !trackQuery.data) return;
+    const track = trackQuery.data;
+    setForm({
+      title: track.title,
+      artistName: track.artistName,
+      albumTitle: track.albumTitle,
+      year: track.year != null ? String(track.year) : '',
+      genre: track.genre ?? '',
+      trackNumber: track.trackNumber != null ? String(track.trackNumber) : '',
+    });
+    setInitialized(true);
+  }, [initialized, trackQuery.data]);
+
+  if (!trackId) {
+    return <ErrorState message={t('metadataEditor.error')} />;
+  }
+
+  if (trackQuery.isLoading || !initialized) {
+    return (
+      <div style={{ padding: '1.5rem' }}>
+        <LoadingSkeleton rows={6} />
+      </div>
+    );
+  }
+
+  if (trackQuery.isError || !trackQuery.data) {
+    return (
+      <ErrorState
+        message={t('metadataEditor.error')}
+        onRetry={() => trackQuery.refetch()}
+      />
+    );
+  }
+
+  const track = trackQuery.data;
+
+  const updateField = (key: keyof FormState) => (value: string) =>
+    setForm((prev) => ({ ...prev, [key]: value }));
+
+  const applyMatch = (match: MetadataMatch) => {
+    setForm((prev) => ({
+      ...prev,
+      title: match.title ?? prev.title,
+      artistName: match.artist ?? prev.artistName,
+      albumTitle: match.album ?? prev.albumTitle,
+      year: match.year != null ? String(match.year) : prev.year,
+    }));
+    setSelectedMatch(null);
+  };
+
+  const handleSave = async () => {
+    await applyMetadata({
+      trackId,
+      edit: {
+        title: form.title.trim() || undefined,
+        artistName: form.artistName.trim() || undefined,
+        albumTitle: form.albumTitle.trim() || undefined,
+        year: form.year.trim() ? Number(form.year) : undefined,
+        genre: form.genre.trim() || undefined,
+        trackNumber: form.trackNumber.trim() ? Number(form.trackNumber) : undefined,
+      },
+    }).unwrap();
+  };
+
   return (
-    <Placeholder title={batch ? t('pages.metadataBatch') : t('pages.metadata')} />
+    <div style={{ display: 'flex', flexDirection: 'column', height: '100%' }}>
+      <div
+        style={{
+          padding: '1.25rem 1.5rem',
+          borderBottom: '1px solid var(--color-border)',
+          display: 'flex',
+          alignItems: 'center',
+          gap: '1rem',
+          flexShrink: 0,
+        }}
+      >
+        <IconButton
+          variant="ghost"
+          size="sm"
+          onClick={() => navigate(-1)}
+          aria-label={t('common.back')}
+        >
+          ←
+        </IconButton>
+        <div style={{ flex: 1, minWidth: 0 }}>
+          <h2 style={{ margin: 0, fontSize: '1.125rem', fontWeight: 700 }}>
+            {t('pages.metadata')}
+          </h2>
+          <p
+            style={{
+              margin: '0.125rem 0 0',
+              fontSize: '0.8125rem',
+              color: 'var(--color-text-3)',
+              overflow: 'hidden',
+              textOverflow: 'ellipsis',
+              whiteSpace: 'nowrap',
+            }}
+          >
+            {track.artistName} · {track.title}
+          </p>
+        </div>
+      </div>
+
+      <ScrollArea style={{ flex: 1 }}>
+        <div
+          style={{
+            padding: '1.5rem',
+            display: 'flex',
+            flexDirection: 'column',
+            gap: '1.25rem',
+            maxWidth: 640,
+          }}
+        >
+          {applyResult.isSuccess && (
+            <Callout variant="success">{t('metadataEditor.saved')}</Callout>
+          )}
+          {applyResult.isError && (
+            <Callout variant="danger">{t('metadataEditor.saveError')}</Callout>
+          )}
+
+          <Card>
+            <div
+              style={{
+                padding: '1.25rem',
+                display: 'flex',
+                flexDirection: 'column',
+                gap: '1rem',
+              }}
+            >
+              <div>
+                <label style={labelStyle}>{t('metadataEditor.fields.title')}</label>
+                <TextField
+                  style={fieldStyle()}
+                  value={form.title}
+                  onChange={(e) => updateField('title')(e.target.value)}
+                />
+              </div>
+              <div>
+                <label style={labelStyle}>{t('metadataEditor.fields.artist')}</label>
+                <TextField
+                  style={fieldStyle()}
+                  value={form.artistName}
+                  onChange={(e) => updateField('artistName')(e.target.value)}
+                />
+              </div>
+              <div>
+                <label style={labelStyle}>{t('metadataEditor.fields.album')}</label>
+                <TextField
+                  style={fieldStyle()}
+                  value={form.albumTitle}
+                  onChange={(e) => updateField('albumTitle')(e.target.value)}
+                />
+              </div>
+              <div style={{ display: 'flex', gap: '1rem' }}>
+                <div style={{ flex: 1 }}>
+                  <label style={labelStyle}>{t('metadataEditor.fields.year')}</label>
+                  <TextField
+                    style={fieldStyle()}
+                    type="number"
+                    value={form.year}
+                    onChange={(e) => updateField('year')(e.target.value)}
+                  />
+                </div>
+                <div style={{ flex: 1 }}>
+                  <label style={labelStyle}>{t('metadataEditor.fields.trackNumber')}</label>
+                  <TextField
+                    style={fieldStyle()}
+                    type="number"
+                    value={form.trackNumber}
+                    onChange={(e) => updateField('trackNumber')(e.target.value)}
+                  />
+                </div>
+              </div>
+              <div>
+                <label style={labelStyle}>{t('metadataEditor.fields.genre')}</label>
+                <TextField
+                  style={fieldStyle()}
+                  value={form.genre}
+                  onChange={(e) => updateField('genre')(e.target.value)}
+                />
+              </div>
+
+              <div style={{ display: 'flex', gap: '0.5rem', justifyContent: 'flex-end' }}>
+                <Button
+                  variant="primary"
+                  onClick={() => void handleSave()}
+                  disabled={applyResult.isLoading}
+                >
+                  {applyResult.isLoading ? <Spinner size="sm" /> : t('metadataEditor.save')}
+                </Button>
+              </div>
+            </div>
+          </Card>
+
+          <Card>
+            <div
+              style={{
+                padding: '1.25rem',
+                display: 'flex',
+                flexDirection: 'column',
+                gap: '1rem',
+              }}
+            >
+              <div
+                style={{
+                  display: 'flex',
+                  alignItems: 'center',
+                  justifyContent: 'space-between',
+                  gap: '0.75rem',
+                }}
+              >
+                <div>
+                  <div style={{ fontWeight: 600, fontSize: '0.9375rem' }}>
+                    {t('metadataEditor.autoEnrich.title')}
+                  </div>
+                  <div style={{ fontSize: '0.8125rem', color: 'var(--color-text-3)' }}>
+                    {t('metadataEditor.autoEnrich.hint')}
+                  </div>
+                </div>
+                <div style={{ display: 'flex', gap: '0.5rem', flexShrink: 0 }}>
+                  <Button
+                    variant="ghost"
+                    size="sm"
+                    onClick={() => void enrichTrack(trackId)}
+                    disabled={enrichResult.isLoading}
+                  >
+                    {enrichResult.isLoading ? (
+                      <Spinner size="sm" />
+                    ) : (
+                      t('metadataEditor.autoEnrich.reEnrich')
+                    )}
+                  </Button>
+                  <Button
+                    variant="primary"
+                    size="sm"
+                    onClick={() => void findMatches(trackId)}
+                    disabled={matchesResult.isFetching}
+                  >
+                    {matchesResult.isFetching ? (
+                      <Spinner size="sm" />
+                    ) : (
+                      t('metadataEditor.autoEnrich.findMatches')
+                    )}
+                  </Button>
+                </div>
+              </div>
+
+              {enrichResult.isSuccess && (
+                <Callout variant="info">{t('metadataEditor.autoEnrich.enqueued')}</Callout>
+              )}
+
+              {matchesResult.isError && (
+                <Callout variant="danger">{t('metadataEditor.autoEnrich.error')}</Callout>
+              )}
+
+              {matchesResult.isSuccess && matchesResult.data && (
+                matchesResult.data.length === 0 ? (
+                  <Callout variant="warning">{t('metadataEditor.autoEnrich.noMatches')}</Callout>
+                ) : (
+                  <div style={{ display: 'flex', flexDirection: 'column', gap: '0.5rem' }}>
+                    {matchesResult.data.map((match) => (
+                      <MatchRow
+                        key={match.acoustid}
+                        match={match}
+                        onUse={() => setSelectedMatch(match)}
+                      />
+                    ))}
+                  </div>
+                )
+              )}
+
+              {selectedMatch && (
+                <DiffView
+                  current={form}
+                  proposed={selectedMatch}
+                  onApply={() => applyMatch(selectedMatch)}
+                  onCancel={() => setSelectedMatch(null)}
+                />
+              )}
+            </div>
+          </Card>
+        </div>
+      </ScrollArea>
+    </div>
+  );
+}
+
+function MatchRow({ match, onUse }: { match: MetadataMatch; onUse: () => void }) {
+  const { t } = useTranslation();
+  const pct = Math.round(match.score * 100);
+  return (
+    <div
+      style={{
+        display: 'flex',
+        alignItems: 'center',
+        gap: '0.75rem',
+        padding: '0.625rem 0.75rem',
+        border: '1px solid var(--color-border)',
+        borderRadius: 8,
+        background: 'var(--color-surface-1)',
+      }}
+    >
+      <Badge variant={pct >= 80 ? 'lime' : pct >= 50 ? 'outline' : 'neutral'}>
+        {pct}%
+      </Badge>
+      <div style={{ flex: 1, minWidth: 0 }}>
+        <div
+          style={{
+            fontSize: '0.875rem',
+            fontWeight: 500,
+            overflow: 'hidden',
+            textOverflow: 'ellipsis',
+            whiteSpace: 'nowrap',
+          }}
+        >
+          {match.title ?? t('metadataEditor.matches.unknownTitle')}
+        </div>
+        <div
+          style={{
+            fontSize: '0.8125rem',
+            color: 'var(--color-text-3)',
+            overflow: 'hidden',
+            textOverflow: 'ellipsis',
+            whiteSpace: 'nowrap',
+          }}
+        >
+          {[match.artist, match.album, match.year]
+            .filter((v) => v !== undefined && v !== null && v !== '')
+            .join(' · ')}
+        </div>
+      </div>
+      <Button variant="ghost" size="sm" onClick={onUse}>
+        {t('metadataEditor.matches.use')}
+      </Button>
+    </div>
+  );
+}
+
+interface DiffRowDef {
+  key: 'title' | 'artistName' | 'albumTitle' | 'year';
+  label: string;
+  current: string;
+  proposed?: string;
+}
+
+function DiffView({
+  current,
+  proposed,
+  onApply,
+  onCancel,
+}: {
+  current: FormState;
+  proposed: MetadataMatch;
+  onApply: () => void;
+  onCancel: () => void;
+}) {
+  const { t } = useTranslation();
+
+  const rows: DiffRowDef[] = [
+    {
+      key: 'title',
+      label: t('metadataEditor.fields.title'),
+      current: current.title,
+      proposed: proposed.title,
+    },
+    {
+      key: 'artistName',
+      label: t('metadataEditor.fields.artist'),
+      current: current.artistName,
+      proposed: proposed.artist,
+    },
+    {
+      key: 'albumTitle',
+      label: t('metadataEditor.fields.album'),
+      current: current.albumTitle,
+      proposed: proposed.album,
+    },
+    {
+      key: 'year',
+      label: t('metadataEditor.fields.year'),
+      current: current.year,
+      proposed: proposed.year != null ? String(proposed.year) : undefined,
+    },
+  ];
+
+  const changed = rows.filter(
+    (row) => row.proposed !== undefined && row.proposed !== row.current,
+  );
+
+  return (
+    <div
+      style={{
+        border: '1px solid var(--color-border)',
+        borderRadius: 8,
+        padding: '0.875rem 1rem',
+        display: 'flex',
+        flexDirection: 'column',
+        gap: '0.625rem',
+        background: 'var(--color-surface-1)',
+      }}
+    >
+      <div style={{ fontWeight: 600, fontSize: '0.875rem' }}>
+        {t('metadataEditor.diff.title')}
+      </div>
+      {changed.length === 0 ? (
+        <div style={{ fontSize: '0.8125rem', color: 'var(--color-text-3)' }}>
+          {t('metadataEditor.diff.noChanges')}
+        </div>
+      ) : (
+        <div style={{ display: 'flex', flexDirection: 'column', gap: '0.375rem' }}>
+          {changed.map((row) => (
+            <div key={row.key} style={{ fontSize: '0.8125rem' }}>
+              <span style={{ color: 'var(--color-text-3)' }}>{row.label}: </span>
+              <span style={{ textDecoration: 'line-through', color: 'var(--color-text-3)' }}>
+                {row.current || '—'}
+              </span>
+              {' → '}
+              <span style={{ color: 'var(--color-accent)', fontWeight: 600 }}>
+                {row.proposed || '—'}
+              </span>
+            </div>
+          ))}
+        </div>
+      )}
+      <div style={{ display: 'flex', gap: '0.5rem', justifyContent: 'flex-end' }}>
+        <Button variant="ghost" size="sm" onClick={onCancel}>
+          {t('metadataEditor.diff.cancel')}
+        </Button>
+        <Button variant="primary" size="sm" onClick={onApply} disabled={changed.length === 0}>
+          {t('metadataEditor.diff.apply')}
+        </Button>
+      </div>
+    </div>
   );
 }

src/features/upload/UploadPage.tsx

@@ -1,4 +1,4 @@
-import { useRef, useState } from 'react';
+import { useEffect, useRef, useState } from 'react';
 import { useNavigate } from 'react-router';
 import { useTranslation } from 'react-i18next';
 import { Badge, Button, Callout, ScrollArea, Spinner } from '@olly/modern-sk';
@@ -6,6 +6,8 @@ import {
   buildUploadFormData,
   useUploadTrackMutation,
 } from '../../api/endpoints/upload';
+import { useGetTrackQuery } from '../../api/endpoints/library';
+import { MetadataStatusBadge } from '../../components/track/MetadataStatusBadge';
 
 /** Pure client-side state — this is a transient upload queue, never server data. */
 type ItemStatus = 'queued' | 'uploading' | 'done' | 'duplicate' | 'error';
@@ -273,11 +275,7 @@ function UploadRow({
             {item.error}
           </div>
         )}
-        {done && (
+        {done && item.trackId && <EnrichmentStatus trackId={item.trackId} />}
-          <div style={{ fontSize: '0.75rem', color: 'var(--color-text-3)' }}>
-            {t('upload.unknownArtist')}
-          </div>
-        )}
       </div>
 
       <StatusBadge status={item.status} />
@@ -301,6 +299,59 @@ function UploadRow({
   );
 }
 
+/**
+ * Polls a just-uploaded track until enrichment settles, then shows the outcome.
+ * Metadata enrichment runs asynchronously in a worker after the upload response
+ * returns, so without polling the row would never reflect the resolved title/
+ * artist or a failure reason. Polling stops (interval → 0) once the status
+ * leaves `pending`.
+ */
+function EnrichmentStatus({ trackId }: { trackId: string }) {
+  const { t } = useTranslation();
+  const [pollMs, setPollMs] = useState(2500);
+  const { data } = useGetTrackQuery(trackId, { pollingInterval: pollMs });
+
+  useEffect(() => {
+    if (data && data.metadataStatus !== 'pending') setPollMs(0);
+  }, [data]);
+
+  const status = data?.metadataStatus ?? 'pending';
+  const resolved =
+    data && data.metadataStatus === 'enriched'
+      ? `${data.artistName} · ${data.title}`
+      : t(`metadata.statusHint.${status}`);
+
+  return (
+    <div
+      style={{
+        display: 'flex',
+        alignItems: 'center',
+        gap: '0.5rem',
+        marginTop: '0.25rem',
+      }}
+    >
+      <MetadataStatusBadge
+        status={status}
+        error={data?.metadataError}
+        hideWhenEnriched={false}
+      />
+      <span
+        style={{
+          fontSize: '0.75rem',
+          color: 'var(--color-text-3)',
+          overflow: 'hidden',
+          textOverflow: 'ellipsis',
+          whiteSpace: 'nowrap',
+        }}
+      >
+        {status === 'failed' && data?.metadataError
+          ? data.metadataError
+          : resolved}
+      </span>
+    </div>
+  );
+}
+
 function StatusBadge({ status }: { status: ItemStatus }) {
   const { t } = useTranslation();
   if (status === 'uploading') {

src/hooks/useConnectionStatus.ts

@@ -3,7 +3,9 @@ import { getApiBaseUrl } from '../config/runtime-config';
 
 type ConnectionStatus = 'connected' | 'connecting' | 'disconnected' | 'error';
 
-export function useConnectionStatus() {
+/** Pings `${baseUrl}/health` (defaults to the active instance's base URL). */
+export function useConnectionStatus(baseUrl?: string) {
+  const url = baseUrl ?? getApiBaseUrl();
   const [status, setStatus] = useState<ConnectionStatus>('connecting');
 
   useEffect(() => {
@@ -13,7 +15,7 @@ export function useConnectionStatus() {
       if (cancelled) return;
       setStatus('connecting');
       try {
-        const res = await fetch(`${getApiBaseUrl()}/health`, {
+        const res = await fetch(`${url}/health`, {
           signal: AbortSignal.timeout(5000),
         });
         if (!cancelled) setStatus(res.ok ? 'connected' : 'error');
@@ -30,7 +32,7 @@ export function useConnectionStatus() {
       cancelled = true;
       clearInterval(interval);
     };
-  }, []);
+  }, [url]);
 
   return status;
 }

src/hooks/useResolvedQueueEntry.ts

@@ -0,0 +1,37 @@
+import { skipToken } from '@reduxjs/toolkit/query';
+import { useGetTrackQuery } from '../api/endpoints/library';
+import type { QueueEntry } from '../store/slices/queue';
+
+export interface ResolvedQueueEntry {
+  trackId: string;
+  title: string;
+  artistName: string;
+  albumTitle: string;
+  durationMs: number;
+  hasCover: boolean;
+}
+
+/**
+ * Merge a queue entry's play-time snapshot with the live `Track` cache.
+ *
+ * The queue slice stores denormalized display fields (title/artist/…) captured
+ * when a track was queued, so they go stale after metadata enrichment updates
+ * the track. This reads through to the RTKQ `Track` cache — invalidated by the
+ * same tags that refresh the library — and prefers its fresh values, falling
+ * back to the snapshot for instant render and offline. Returns undefined when
+ * there is no current entry.
+ */
+export function useResolvedQueueEntry(
+  entry: QueueEntry | undefined,
+): ResolvedQueueEntry | undefined {
+  const { data } = useGetTrackQuery(entry?.trackId ?? skipToken);
+  if (!entry) return undefined;
+  return {
+    trackId: entry.trackId,
+    title: data?.title ?? entry.title,
+    artistName: data?.artistName ?? entry.artistName,
+    albumTitle: data?.albumTitle ?? entry.albumTitle,
+    durationMs: data?.durationMs ?? entry.durationMs,
+    hasCover: data?.hasCover ?? false,
+  };
+}

src/hooks/useStreamCached.ts

@@ -0,0 +1,30 @@
+import { useEffect, useState } from 'react';
+import { useAppSelector } from './useAppDispatch';
+import { isStreamCached } from '../lib/sw';
+import { getStreamUrl } from '../api/endpoints/streaming';
+
+/**
+ * Whether the given track is available from the offline audio cache (Tier 3).
+ * Drives the player-bar source indicator (local vs streaming). Returns false
+ * until the service worker is controlling and confirms a hit.
+ */
+export function useStreamCached(trackId: string | undefined): boolean {
+  const token = useAppSelector((s) => s.auth.accessToken);
+  const [cached, setCached] = useState(false);
+
+  useEffect(() => {
+    if (!trackId || !token) {
+      setCached(false);
+      return;
+    }
+    let active = true;
+    void isStreamCached(getStreamUrl(trackId, token)).then((hit) => {
+      if (active) setCached(hit);
+    });
+    return () => {
+      active = false;
+    };
+  }, [trackId, token]);
+
+  return cached;
+}

src/i18n/locales/en.ts

@@ -17,6 +17,7 @@ const en = {
     disconnected: 'Offline',
     error: 'Unreachable',
     manage: 'Connection — manage instances',
+    cached: 'Showing last-seen data',
   },
   user: {
     online: 'online',
@@ -24,18 +25,46 @@ const en = {
     signOut: 'Sign out',
   },
   connect: {
-    savedInstances: 'Saved instances',
+    domains: {
-    active: 'active',
+      title: 'Saved instances',
-    use: 'Use',
+      addPlaceholder: 'https://your-server.example.com',
-    forgetTitle: 'Forget this instance',
+      addButton: 'Add instance',
-    form: {
+      selected: 'Selected',
-      title: 'Connect to a backend',
+      use: 'Use',
-      serverUrl: 'Server URL',
+      forgetTitle: 'Remove this instance',
+    },
+    removeDialog: {
+      title: 'Remove cached data?',
+      description:
+        'This removes "{{name}}" from your saved instances and clears its cached data on this device.',
+      cancel: 'Cancel',
+      logout: 'Just log out',
+      removeAndLogout: 'Remove data & log out',
+    },
+    login: {
+      title: 'Log in to {{name}}',
+      registerTitle: 'Sign up for {{name}}',
       username: 'Username',
       password: 'Password',
-      submit: 'Connect',
+      passwordHint: 'At least 8 characters.',
-      stubNote:
+      submit: 'Log in',
-        'Stub mode — backend not wired. Connect signs in with a fake admin session, scoped to this instance.',
+      submitting: 'Logging in…',
+      registerSubmit: 'Sign up',
+      registering: 'Signing up…',
+      noAccount: "Don't have an account?",
+      registerLink: 'Sign up',
+      haveAccount: 'Already have an account?',
+      signInLink: 'Log in',
+    },
+    errors: {
+      unreachable:
+        "Can't reach this server. Check the URL and that it's online.",
+      badCredentials: 'Incorrect username or password.',
+      generic: 'Sign-in failed. Please try again.',
+      usernameTaken: 'That username is already taken.',
+      passwordTooShort: 'Password must be at least 8 characters.',
+      registrationDisabled: 'Registration is disabled on this server.',
+      registerFailed: 'Could not create the account. Please try again.',
     },
   },
   library: {
@@ -127,12 +156,49 @@ const en = {
       playNow: 'Play now',
       playNext: 'Play next',
       addToQueue: 'Add to queue',
+      info: 'Track info',
       addToPlaylist: 'Add to playlist…',
       editMetadata: 'Edit metadata',
       download: 'Download',
       delete: 'Delete',
     },
   },
+  trackInfo: {
+    title: 'Track info',
+    open: 'View track info',
+    close: 'Close',
+    notFound: 'Track not found',
+    play: 'Play',
+    addToQueue: 'Queue',
+    editMetadata: 'Edit metadata',
+    liked: 'Liked',
+    trackOf: 'No. {{n}} of {{total}}',
+    kbps: '{{n}} kbps',
+    sections: {
+      status: 'Status',
+      general: 'General',
+      file: 'File',
+      identifiers: 'Identifiers',
+    },
+    fields: {
+      artist: 'Artist',
+      album: 'Album',
+      trackNumber: 'Track',
+      disc: 'Disc',
+      year: 'Year',
+      genre: 'Genre',
+      duration: 'Duration',
+      format: 'Format',
+      bitrate: 'Bitrate',
+      size: 'Size',
+      source: 'Source',
+      added: 'Added',
+      enriched: 'Enriched',
+      trackId: 'Track ID',
+      albumId: 'Album ID',
+      artistId: 'Artist ID',
+    },
+  },
   common: {
     error: 'Something went wrong',
     retry: 'Retry',
@@ -201,11 +267,60 @@ const en = {
       error: 'Failed',
     },
   },
+  metadata: {
+    status: {
+      pending: 'Enriching…',
+      enriched: 'Enriched',
+      failed: 'No match',
+      manual: 'Manual',
+    },
+    statusHint: {
+      pending: 'Identifying metadata…',
+      enriched: 'Metadata identified',
+      failed: 'Metadata could not be identified',
+      manual: 'Edited manually — not auto-updated',
+    },
+  },
+  metadataEditor: {
+    error: 'Failed to load track',
+    saved: 'Metadata saved.',
+    saveError: 'Failed to save metadata.',
+    save: 'Save',
+    fields: {
+      title: 'Title',
+      artist: 'Artist',
+      album: 'Album',
+      year: 'Year',
+      genre: 'Genre',
+      trackNumber: 'Track number',
+    },
+    autoEnrich: {
+      title: 'AcoustID lookup',
+      hint: 'Identify this track by audio fingerprint.',
+      findMatches: 'Find matches',
+      reEnrich: 'Re-run enrichment',
+      enqueued: 'Enrichment queued — refresh in a moment.',
+      error: 'Could not look up matches.',
+      noMatches: 'No matches found.',
+    },
+    matches: {
+      use: 'Use',
+      unknownTitle: 'Unknown title',
+    },
+    diff: {
+      title: 'Apply this match?',
+      noChanges: 'No changes from current values.',
+      cancel: 'Cancel',
+      apply: 'Apply',
+    },
+  },
 } as const;
 
 export default en;
 
 type DeepString<T> = {
-  [K in keyof T]: T[K] extends Record<string, unknown> ? DeepString<T[K]> : string;
+  [K in keyof T]: T[K] extends Record<string, unknown>
+    ? DeepString<T[K]>
+    : string;
 };
 export type Translations = DeepString<typeof en>;

src/i18n/locales/ru.ts

@@ -19,6 +19,7 @@ const ru: Translations = {
     disconnected: 'Нет связи',
     error: 'Недоступно',
     manage: 'Соединение — управление экземплярами',
+    cached: 'Показаны последние данные',
   },
   user: {
     online: 'онлайн',
@@ -26,18 +27,46 @@ const ru: Translations = {
     signOut: 'Выйти',
   },
   connect: {
-    savedInstances: 'Сохранённые серверы',
+    domains: {
-    active: 'активный',
+      title: 'Сохранённые серверы',
-    use: 'Выбрать',
+      addPlaceholder: 'https://your-server.example.com',
-    forgetTitle: 'Забыть этот сервер',
+      addButton: 'Добавить сервер',
-    form: {
+      selected: 'Выбран',
-      title: 'Подключиться к серверу',
+      use: 'Выбрать',
-      serverUrl: 'URL сервера',
+      forgetTitle: 'Удалить этот сервер',
+    },
+    removeDialog: {
+      title: 'Удалить локальные данные?',
+      description:
+        'Сервер «{{name}}» будет удалён из сохранённых, а его данные на этом устройстве — очищены.',
+      cancel: 'Отмена',
+      logout: 'Просто выйти',
+      removeAndLogout: 'Удалить данные и выйти',
+    },
+    login: {
+      title: 'Вход в {{name}}',
+      registerTitle: 'Регистрация на {{name}}',
       username: 'Имя пользователя',
       password: 'Пароль',
-      submit: 'Подключиться',
+      passwordHint: 'Не менее 8 символов.',
-      stubNote:
+      submit: 'Войти',
-        'Режим заглушки — сервер не подключён. Создаётся фиктивная сессия администратора для этого экземпляра.',
+      submitting: 'Вход…',
+      registerSubmit: 'Зарегистрироваться',
+      registering: 'Регистрация…',
+      noAccount: 'Нет аккаунта?',
+      registerLink: 'Зарегистрироваться',
+      haveAccount: 'Уже есть аккаунт?',
+      signInLink: 'Войти',
+    },
+    errors: {
+      unreachable:
+        'Не удаётся подключиться к серверу. Проверьте URL и доступность.',
+      badCredentials: 'Неверное имя пользователя или пароль.',
+      generic: 'Не удалось войти. Попробуйте ещё раз.',
+      usernameTaken: 'Это имя пользователя уже занято.',
+      passwordTooShort: 'Пароль должен содержать не менее 8 символов.',
+      registrationDisabled: 'Регистрация на этом сервере отключена.',
+      registerFailed: 'Не удалось создать аккаунт. Попробуйте ещё раз.',
     },
   },
   library: {
@@ -129,12 +158,49 @@ const ru: Translations = {
       playNow: 'Играть сейчас',
       playNext: 'Следующим',
       addToQueue: 'Добавить в очередь',
+      info: 'Информация о треке',
       addToPlaylist: 'Добавить в плейлист…',
       editMetadata: 'Редактировать метаданные',
       download: 'Скачать',
       delete: 'Удалить',
     },
   },
+  trackInfo: {
+    title: 'О треке',
+    open: 'Информация о треке',
+    close: 'Закрыть',
+    notFound: 'Трек не найден',
+    play: 'Играть',
+    addToQueue: 'В очередь',
+    editMetadata: 'Метаданные',
+    liked: 'В избранном',
+    trackOf: '№ {{n}} из {{total}}',
+    kbps: '{{n}} кбит/с',
+    sections: {
+      status: 'Статус',
+      general: 'Основное',
+      file: 'Файл',
+      identifiers: 'Идентификаторы',
+    },
+    fields: {
+      artist: 'Исполнитель',
+      album: 'Альбом',
+      trackNumber: 'Трек',
+      disc: 'Диск',
+      year: 'Год',
+      genre: 'Жанр',
+      duration: 'Длительность',
+      format: 'Формат',
+      bitrate: 'Битрейт',
+      size: 'Размер',
+      source: 'Источник',
+      added: 'Добавлен',
+      enriched: 'Обогащён',
+      trackId: 'ID трека',
+      albumId: 'ID альбома',
+      artistId: 'ID исполнителя',
+    },
+  },
   common: {
     error: 'Что-то пошло не так',
     retry: 'Повторить',
@@ -203,6 +269,53 @@ const ru: Translations = {
       error: 'Ошибка',
     },
   },
+  metadata: {
+    status: {
+      pending: 'Обработка…',
+      enriched: 'Готово',
+      failed: 'Нет совпадения',
+      manual: 'Вручную',
+    },
+    statusHint: {
+      pending: 'Определяем метаданные…',
+      enriched: 'Метаданные определены',
+      failed: 'Не удалось определить метаданные',
+      manual: 'Изменено вручную — не обновляется автоматически',
+    },
+  },
+  metadataEditor: {
+    error: 'Не удалось загрузить трек',
+    saved: 'Метаданные сохранены.',
+    saveError: 'Не удалось сохранить метаданные.',
+    save: 'Сохранить',
+    fields: {
+      title: 'Название',
+      artist: 'Исполнитель',
+      album: 'Альбом',
+      year: 'Год',
+      genre: 'Жанр',
+      trackNumber: 'Номер трека',
+    },
+    autoEnrich: {
+      title: 'Поиск по AcoustID',
+      hint: 'Определить трек по аудио-отпечатку.',
+      findMatches: 'Найти совпадения',
+      reEnrich: 'Повторить обогащение',
+      enqueued: 'Обогащение запущено — обновите через момент.',
+      error: 'Не удалось найти совпадения.',
+      noMatches: 'Совпадений не найдено.',
+    },
+    matches: {
+      use: 'Использовать',
+      unknownTitle: 'Неизвестное название',
+    },
+    diff: {
+      title: 'Применить это совпадение?',
+      noChanges: 'Нет изменений относительно текущих значений.',
+      cancel: 'Отмена',
+      apply: 'Применить',
+    },
+  },
 };
 
 export default ru;

src/index.tsx

@@ -10,6 +10,7 @@ import { BrowserRouter } from 'react-router';
 import { ThemeProvider, TooltipProvider } from '@olly/modern-sk';
 import { store } from './store';
 import { AppRoutes } from './routes';
+import { registerServiceWorker } from './lib/sw';
 
 // Import all endpoint injections to ensure they are registered
 import './api/endpoints/auth';
@@ -21,6 +22,10 @@ import './api/endpoints/storage';
 import './api/endpoints/admin';
 import './api/endpoints/upload';
 
+// Tier 3 offline: register the audio-caching service worker (no-op if the
+// browser/origin doesn't support it).
+registerServiceWorker();
+
 const rootEl = document.getElementById('root');
 if (rootEl) {
   // grained black-ish background + base text color from modern-sk

src/lib/format.ts

@@ -16,6 +16,16 @@ export function formatFileSize(bytes: number): string {
   return `${(bytes / (1024 * 1024 * 1024)).toFixed(2)} GB`;
 }
 
+export function formatDateTime(iso: string | undefined): string | undefined {
+  if (!iso) return undefined;
+  const d = new Date(iso);
+  if (Number.isNaN(d.getTime())) return undefined;
+  return new Intl.DateTimeFormat(undefined, {
+    dateStyle: 'medium',
+    timeStyle: 'short',
+  }).format(d);
+}
+
 export function formatCount(n: number): string {
   if (n < 1000) return String(n);
   if (n < 1_000_000) return `${(n / 1000).toFixed(1)}K`;

src/lib/sw.ts

@@ -0,0 +1,80 @@
+/*
+ * Service-worker client: registration + a typed bridge to the audio offline
+ * cache (Tier 3). The SW itself lives in `public/sw.js`; this is the app side.
+ *
+ * Messaging uses a MessageChannel — we hand the SW a port and await its reply —
+ * so each call resolves with that request's result rather than a global event.
+ */
+
+export interface AudioCacheStats {
+  count: number;
+  bytes: number;
+  maxBytes: number;
+}
+
+/** Register the service worker. No-op when unsupported (e.g. plain http host). */
+export function registerServiceWorker(): void {
+  if (typeof navigator === 'undefined' || !('serviceWorker' in navigator)) {
+    return;
+  }
+  window.addEventListener('load', () => {
+    // Module worker: sw.js uses ES imports (see public/sw.js + sw-core.js).
+    navigator.serviceWorker.register('/sw.js', { type: 'module' }).catch(() => {
+      /* SW unavailable (insecure origin, blocked, …) — app still works online */
+    });
+  });
+}
+
+function controller(): ServiceWorker | null {
+  if (typeof navigator === 'undefined' || !('serviceWorker' in navigator)) {
+    return null;
+  }
+  return navigator.serviceWorker.controller;
+}
+
+/** Round-trip a message to the SW; rejects if no controlling SW is present. */
+function send<T>(message: Record<string, unknown>): Promise<T> {
+  const sw = controller();
+  if (!sw) return Promise.reject(new Error('no-service-worker'));
+  return new Promise<T>((resolve, reject) => {
+    const channel = new MessageChannel();
+    channel.port1.onmessage = (event) => resolve(event.data as T);
+    try {
+      sw.postMessage(message, [channel.port2]);
+    } catch (err) {
+      reject(err as Error);
+    }
+  });
+}
+
+/** Total size + count of cached audio, or null when the SW isn't controlling. */
+export async function getAudioCacheStats(): Promise<AudioCacheStats | null> {
+  try {
+    return await send<AudioCacheStats>({ type: 'STATS' });
+  } catch {
+    return null;
+  }
+}
+
+/** Whether a given stream URL is already cached for offline playback. */
+export async function isStreamCached(streamUrl: string): Promise<boolean> {
+  try {
+    const { cached } = await send<{ cached: boolean }>({
+      type: 'HAS',
+      url: streamUrl,
+    });
+    return cached;
+  } catch {
+    return false;
+  }
+}
+
+/** Drop the entire audio cache. Resolves false if the SW isn't controlling. */
+export async function clearAudioCache(): Promise<boolean> {
+  try {
+    const { ok } = await send<{ ok: boolean }>({ type: 'CLEAR' });
+    return ok;
+  } catch {
+    return false;
+  }
+}

src/store/index.ts

@@ -4,6 +4,8 @@ import authReducer from './slices/auth';
 import playerReducer from './slices/player';
 import queueReducer from './slices/queue';
 import uiReducer from './slices/ui';
+import { loadPlayerState, loadQueueState, startPersistence } from './persist';
+import { rehydrateApiCache, startApiPersistence } from './rtkqPersist';
 
 export const store = configureStore({
   reducer: {
@@ -13,9 +15,23 @@ export const store = configureStore({
     queue: queueReducer,
     ui: uiReducer,
   },
+  // Tier 1 offline: rehydrate queue/player from the active backend's namespace
+  // so a reload (even with no backend) restores exactly where the user left off.
+  preloadedState: {
+    queue: loadQueueState(),
+    player: loadPlayerState(),
+  },
   middleware: (getDefaultMiddleware) =>
     getDefaultMiddleware().concat(api.middleware),
 });
 
+// Flush queue/player changes back to localStorage (throttled).
+startPersistence(store);
+
+// Tier 2 offline: replay the last-seen RTKQ cache, then keep snapshotting it.
+// Rehydrate first so cached server data is present before any component mounts.
+rehydrateApiCache(store.dispatch);
+startApiPersistence(store);
+
 export type RootState = ReturnType<typeof store.getState>;
 export type AppDispatch = typeof store.dispatch;

src/store/persist.ts

@@ -0,0 +1,123 @@
+/*
+ * Tier 1 offline support: persist client state (queue + player) to the active
+ * backend's localStorage namespace, mirroring the auth slice. This is what lets
+ * the UI come back exactly as the user left it after a reload with no backend
+ * reachable — no server data is duplicated (the queue stores track IDs + minimal
+ * display fields only; full track records still live in the RTKQ cache).
+ *
+ * Server data (library/albums/…) is Tier 2 (see `rtkqPersist.ts`).
+ */
+import { instanceStorage } from '../config/instances';
+import {
+  queueInitialState,
+  type QueueState,
+} from './slices/queue';
+import {
+  playerInitialState,
+  type PlayerState,
+} from './slices/player';
+import type { RootState } from './index';
+
+const QUEUE_KEY = 'queue';
+const PLAYER_KEY = 'player';
+
+// Only persist fields that make sense to restore. `duration`/`isPlaying` are
+// derived from the <audio> element on next load, and the panel toggles are
+// transient UI, so they are intentionally left out.
+type PersistedQueue = Pick<
+  QueueState,
+  'entries' | 'currentIndex' | 'source' | 'sourceId' | 'sourceName'
+>;
+type PersistedPlayer = Pick<
+  PlayerState,
+  'currentTrackId' | 'position' | 'volume' | 'muted' | 'repeat' | 'shuffle'
+>;
+
+function pickQueue(state: QueueState): PersistedQueue {
+  return {
+    entries: state.entries,
+    currentIndex: state.currentIndex,
+    source: state.source,
+    sourceId: state.sourceId,
+    sourceName: state.sourceName,
+  };
+}
+
+function pickPlayer(state: PlayerState): PersistedPlayer {
+  return {
+    currentTrackId: state.currentTrackId,
+    position: state.position,
+    volume: state.volume,
+    muted: state.muted,
+    repeat: state.repeat,
+    shuffle: state.shuffle,
+  };
+}
+
+function read<T>(key: string): Partial<T> | null {
+  try {
+    const raw = instanceStorage.get(key);
+    return raw ? (JSON.parse(raw) as Partial<T>) : null;
+  } catch {
+    return null;
+  }
+}
+
+/** Build the queue slice's initial state, restoring any persisted queue. */
+export function loadQueueState(): QueueState {
+  const persisted = read<PersistedQueue>(QUEUE_KEY);
+  if (!persisted) return queueInitialState;
+  const merged: QueueState = { ...queueInitialState, ...persisted };
+  // Guard the index against a corrupted/short entries array.
+  if (
+    merged.currentIndex >= merged.entries.length ||
+    merged.currentIndex < -1
+  ) {
+    merged.currentIndex = merged.entries.length ? 0 : -1;
+  }
+  return merged;
+}
+
+/** Build the player slice's initial state, restoring any persisted player. */
+export function loadPlayerState(): PlayerState {
+  const persisted = read<PersistedPlayer>(PLAYER_KEY);
+  if (!persisted) return playerInitialState;
+  // Never auto-resume playback on load: browsers block autoplay and the
+  // <audio> element starts paused regardless. isPlaying stays false.
+  return { ...playerInitialState, ...persisted, isPlaying: false };
+}
+
+/**
+ * Subscribe a store so queue/player changes are flushed to localStorage. The
+ * write is throttled because `setPosition` fires several times a second during
+ * playback — without throttling we'd hammer localStorage on every tick.
+ */
+export function startPersistence(store: {
+  getState: () => RootState;
+  subscribe: (listener: () => void) => () => void;
+}): () => void {
+  const initial = store.getState();
+  let lastQueue = JSON.stringify(pickQueue(initial.queue));
+  let lastPlayer = JSON.stringify(pickPlayer(initial.player));
+  let timer: ReturnType<typeof setTimeout> | null = null;
+
+  const flush = () => {
+    timer = null;
+    const state = store.getState();
+    const queueSnapshot = JSON.stringify(pickQueue(state.queue));
+    if (queueSnapshot !== lastQueue) {
+      instanceStorage.set(QUEUE_KEY, queueSnapshot);
+      lastQueue = queueSnapshot;
+    }
+    const playerSnapshot = JSON.stringify(pickPlayer(state.player));
+    if (playerSnapshot !== lastPlayer) {
+      instanceStorage.set(PLAYER_KEY, playerSnapshot);
+      lastPlayer = playerSnapshot;
+    }
+  };
+
+  return store.subscribe(() => {
+    if (timer) return;
+    timer = setTimeout(flush, 1000);
+  });
+}

src/store/rtkqPersist.ts

@@ -0,0 +1,86 @@
+/*
+ * Tier 2 offline support: persist the RTK Query cache (last-seen server data —
+ * library/albums/artists/…) to the active backend's localStorage namespace and
+ * replay it into the cache on startup. With the backend down, components keep
+ * rendering the last-known data read-only instead of an error state.
+ *
+ * Per the architecture invariant, server data is NOT copied into a slice: this
+ * snapshots the RTKQ cache itself and feeds it back through RTKQ's own
+ * `extractRehydrationInfo` mechanism (see `api/index.ts`).
+ */
+import { instanceStorage } from '../config/instances';
+import { rehydrateApi, type RehydrateApiPayload } from '../api/rehydrate';
+import type { RootState } from './index';
+
+const CACHE_KEY = 'rtkq';
+
+type ApiState = RootState['api'];
+type QueryEntry = ApiState['queries'][string];
+
+/**
+ * Keep only successfully-fulfilled query results — pending/rejected entries
+ * carry no usable data and subscriptions are rebuilt by components on mount.
+ * Mutation results are never restored.
+ */
+const EMPTY_PROVIDED = { tags: {}, keys: {} };
+
+function snapshot(apiState: ApiState): RehydrateApiPayload {
+  const queries: Record<string, unknown> = {};
+  for (const [key, entry] of Object.entries(apiState.queries)) {
+    const q = entry as QueryEntry | undefined;
+    if (q && q.status === 'fulfilled') queries[key] = q;
+  }
+  // Carry `provided` along so RTKQ can re-register invalidation tags for the
+  // restored entries; it is also required structurally (see RehydrateApiPayload).
+  return { queries, mutations: {}, provided: apiState.provided ?? EMPTY_PROVIDED };
+}
+
+function load(): RehydrateApiPayload | null {
+  try {
+    const raw = instanceStorage.get(CACHE_KEY);
+    if (!raw) return null;
+    const parsed = JSON.parse(raw) as Partial<RehydrateApiPayload>;
+    if (!parsed.queries) return null;
+    // `provided` may be absent in snapshots written before this field existed —
+    // default it so the invalidation slice doesn't crash on `provided.tags`.
+    return {
+      queries: parsed.queries,
+      mutations: {},
+      provided: parsed.provided ?? EMPTY_PROVIDED,
+    };
+  } catch {
+    return null;
+  }
+}
+
+/** Replay the persisted cache into RTKQ. Call once after the store is created. */
+export function rehydrateApiCache(dispatch: (action: unknown) => void): void {
+  const cached = load();
+  if (cached) dispatch(rehydrateApi(cached));
+}
+
+/**
+ * Subscribe a store so the RTKQ cache is flushed to localStorage. Throttled,
+ * since cache state churns on every in-flight query transition.
+ */
+export function startApiPersistence(store: {
+  getState: () => RootState;
+  subscribe: (listener: () => void) => () => void;
+}): () => void {
+  let last = '';
+  let timer: ReturnType<typeof setTimeout> | null = null;
+
+  const flush = () => {
+    timer = null;
+    const snap = JSON.stringify(snapshot(store.getState().api));
+    if (snap !== last) {
+      instanceStorage.set(CACHE_KEY, snap);
+      last = snap;
+    }
+  };
+
+  return store.subscribe(() => {
+    if (timer) return;
+    timer = setTimeout(flush, 2000);
+  });
+}

src/store/slices/auth.ts

@@ -38,12 +38,16 @@ export const authSlice = createSlice({
       action: PayloadAction<{
         accessToken: string;
         refreshToken: string;
-        expiresIn: number;
+        expiresIn?: number;
       }>,
     ) {
       state.accessToken = action.payload.accessToken;
       state.refreshToken = action.payload.refreshToken;
-      state.expiresAt = Date.now() + action.payload.expiresIn * 1000;
+      // Backends that omit a TTL leave expiresAt null — reauth is 401-driven.
+      state.expiresAt =
+        action.payload.expiresIn != null
+          ? Date.now() + action.payload.expiresIn * 1000
+          : null;
       persistAuth(state);
     },
     setUser(state, action: PayloadAction<User>) {

src/store/slices/player.ts

@@ -1,8 +1,8 @@
 import { createSlice, type PayloadAction } from '@reduxjs/toolkit';
 
-type RepeatMode = 'none' | 'one' | 'all';
+export type RepeatMode = 'none' | 'one' | 'all';
 
-interface PlayerState {
+export interface PlayerState {
   currentTrackId: string | null;
   isPlaying: boolean;
   position: number;
@@ -11,11 +11,10 @@ interface PlayerState {
   muted: boolean;
   repeat: RepeatMode;
   shuffle: boolean;
-  isNowPlayingOpen: boolean;
   isQueueOpen: boolean;
 }
 
-const initialState: PlayerState = {
+export const playerInitialState: PlayerState = {
   currentTrackId: null,
   isPlaying: false,
   position: 0,
@@ -24,15 +23,12 @@ const initialState: PlayerState = {
   muted: false,
   repeat: 'none',
   shuffle: false,
-  isNowPlayingOpen: false,
+  isQueueOpen: false,
-  // STUB: open by default so the queue drawer look is visible before a backend
-  // exists (pairs with DEMO_QUEUE). Default to false once real playback lands.
-  isQueueOpen: true,
 };
 
 export const playerSlice = createSlice({
   name: 'player',
-  initialState,
+  initialState: playerInitialState,
   reducers: {
     play(state, action: PayloadAction<string>) {
       state.currentTrackId = action.payload;
@@ -68,9 +64,6 @@ export const playerSlice = createSlice({
     toggleShuffle(state) {
       state.shuffle = !state.shuffle;
     },
-    toggleNowPlaying(state) {
-      state.isNowPlayingOpen = !state.isNowPlayingOpen;
-    },
     toggleQueue(state) {
       state.isQueueOpen = !state.isQueueOpen;
     },
@@ -88,7 +81,6 @@ export const {
   toggleMute,
   setRepeat,
   toggleShuffle,
-  toggleNowPlaying,
   toggleQueue,
 } = playerSlice.actions;
 export default playerSlice.reducer;

src/store/slices/queue.ts

@@ -1,6 +1,6 @@
 import { createSlice, type PayloadAction } from '@reduxjs/toolkit';
 
-type QueueSource =
+export type QueueSource =
   | 'manual'
   | 'album'
   | 'playlist'
@@ -8,7 +8,7 @@ type QueueSource =
   | 'search'
   | 'radio';
 
-interface QueueEntry {
+export interface QueueEntry {
   trackId: string;
   title: string;
   artistName: string;
@@ -17,7 +17,7 @@ interface QueueEntry {
   albumArtUrl?: string;
 }
 
-interface QueueState {
+export interface QueueState {
   entries: QueueEntry[];
   currentIndex: number;
   source: QueueSource;
@@ -25,52 +25,17 @@ interface QueueState {
   sourceName: string | null;
 }
 
-// STUB demo queue — purely client-side display data so the player bar and
+export const queueInitialState: QueueState = {
-// queue drawer render with content before the backend exists. Delete this
+  entries: [],
-// block (reset entries/currentIndex/source to the empty values) once real
+  currentIndex: -1,
-// playback wires tracks into the queue.
+  source: 'manual',
-const DEMO_QUEUE: QueueEntry[] = [
-  {
-    trackId: 'd1',
-    title: 'Quiet Storage',
-    artistName: 'Cyan Atlas',
-    albumTitle: 'Night Index',
-    durationMs: 312_000,
-  },
-  {
-    trackId: 'd2',
-    title: 'Magnetic North',
-    artistName: 'Tidal Bloom',
-    albumTitle: 'Ferric Coast',
-    durationMs: 243_000,
-  },
-  {
-    trackId: 'd3',
-    title: 'Ambergris',
-    artistName: 'Møller',
-    albumTitle: 'Warm Static',
-    durationMs: 201_000,
-  },
-  {
-    trackId: 'd4',
-    title: 'Slow Carrier',
-    artistName: 'Tidal Bloom',
-    albumTitle: 'Ferric Coast',
-    durationMs: 301_000,
-  },
-];
-
-const initialState: QueueState = {
-  entries: DEMO_QUEUE,
-  currentIndex: 0,
-  source: 'radio',
   sourceId: null,
-  sourceName: 'My radio',
+  sourceName: null,
 };
 
 export const queueSlice = createSlice({
   name: 'queue',
-  initialState,
+  initialState: queueInitialState,
   reducers: {
     setQueue(
       state,

src/store/slices/ui.ts

@@ -4,12 +4,15 @@ interface UiState {
   sidebarCollapsed: boolean;
   activeModal: string | null;
   activeTrackContextMenuId: string | null;
+  /** Track whose info drawer is open (rightmost drawer); null = closed. */
+  trackInfoId: string | null;
 }
 
 const initialState: UiState = {
   sidebarCollapsed: false,
   activeModal: null,
   activeTrackContextMenuId: null,
+  trackInfoId: null,
 };
 
 export const uiSlice = createSlice({
@@ -31,6 +34,12 @@ export const uiSlice = createSlice({
     setActiveContextMenu(state, action: PayloadAction<string | null>) {
       state.activeTrackContextMenuId = action.payload;
     },
+    openTrackInfo(state, action: PayloadAction<string>) {
+      state.trackInfoId = action.payload;
+    },
+    closeTrackInfo(state) {
+      state.trackInfoId = null;
+    },
   },
 });
 
@@ -40,5 +49,7 @@ export const {
   openModal,
   closeModal,
   setActiveContextMenu,
+  openTrackInfo,
+  closeTrackInfo,
 } = uiSlice.actions;
 export default uiSlice.reducer;

src/styles/global.css

@@ -28,6 +28,11 @@ body {
   margin: 0;
   font-family: var(--font-sans);
   color: var(--fg-1);
+  /* Paint the themed background immediately. The inline theme script in
+     index.html (see rsbuild.config.ts) sets [data-theme] before first paint, so
+     --color-bg resolves to the right value here before React mounts #root and
+     layers the .modern-sk-felt grain on top — no flash of white. */
+  background: var(--color-bg);
   -webkit-font-smoothing: antialiased;
 }
 

src/styles/shell.css

@@ -724,6 +724,164 @@
   font-size: 12px;
 }
 
+/* ============================================================
+   TRACK INFO DRAWER (rightmost — sits right of the queue drawer)
+   ============================================================ */
+/* Same width-collapse pattern as .qd. Rendered after QueuePanel in AppShell so
+   when both are open this is the rightmost panel. */
+.tid {
+  width: 360px;
+  flex-shrink: 0;
+  overflow: hidden;
+  border-left: 1px solid var(--hair);
+  background: linear-gradient(180deg, rgba(0, 0, 0, 0.12), rgba(0, 0, 0, 0.24));
+  transition:
+    width 0.24s var(--ease-out),
+    border-left-color 0.24s var(--ease-out);
+}
+.tid.closed {
+  width: 0;
+  border-left-color: transparent;
+}
+.tid-inner {
+  width: 360px;
+  height: 100%;
+  display: flex;
+  flex-direction: column;
+  min-height: 0;
+}
+.tid-head {
+  flex-shrink: 0;
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 16px 18px 12px;
+  border-bottom: 1px solid var(--hair);
+}
+.tid-head h3 {
+  margin: 0;
+  font-size: 15px;
+  font-weight: 700;
+  color: var(--fg-1);
+}
+.tid-scroll {
+  flex: 1;
+  min-height: 0;
+  overflow-y: auto;
+  padding: 18px;
+}
+.tid-cover {
+  width: 100%;
+  aspect-ratio: 1 / 1;
+  margin-bottom: 16px;
+  border-radius: 12px;
+  overflow: hidden;
+  background: var(--steel-900);
+  box-shadow: var(--shadow-raised, 0 8px 24px rgba(0, 0, 0, 0.4));
+}
+.tid-cover img {
+  width: 100%;
+  height: 100%;
+  object-fit: cover;
+  display: block;
+}
+.tid-title {
+  margin: 0 0 4px;
+  font-size: 19px;
+  font-weight: 700;
+  color: var(--fg-1);
+  line-height: 1.25;
+}
+.tid-sub {
+  display: block;
+  font-size: 13px;
+  color: var(--fg-2);
+  text-decoration: none;
+}
+.tid-sub:hover {
+  color: var(--lime);
+  text-decoration: underline;
+}
+.tid-album {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  margin-top: 3px;
+  color: var(--fg-3);
+}
+.tid-actions {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 8px;
+  margin: 16px 0 4px;
+}
+.tid-section {
+  margin-top: 18px;
+  padding-top: 14px;
+  border-top: 1px solid var(--hair);
+}
+.tid-section-label {
+  display: block;
+  margin-bottom: 10px;
+}
+.tid-status {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 8px;
+}
+.tid-error {
+  margin: 8px 0 0;
+  font-size: 12px;
+  color: var(--ember, #e9572b);
+}
+.tid-row {
+  display: flex;
+  gap: 12px;
+  padding: 5px 0;
+  font-size: 13px;
+}
+.tid-row-k {
+  flex-shrink: 0;
+  width: 96px;
+  color: var(--fg-3);
+}
+.tid-row-v {
+  min-width: 0;
+  flex: 1;
+  color: var(--fg-1);
+  text-align: right;
+  word-break: break-word;
+}
+.tid-row-v.mono {
+  font-family: var(--font-mono, ui-monospace, monospace);
+  font-size: 11px;
+  color: var(--fg-2);
+}
+
+/* On narrower viewports the drawer overlays the content instead of pushing it,
+   so the queue + info drawers don't squeeze the main screen. */
+@media (max-width: 1180px) {
+  .app-body {
+    position: relative;
+  }
+  .tid {
+    position: absolute;
+    top: 0;
+    right: 0;
+    bottom: 0;
+    width: 360px;
+    z-index: 30;
+    box-shadow: -16px 0 40px rgba(0, 0, 0, 0.5);
+    transition: transform 0.24s var(--ease-out);
+  }
+  .tid.closed {
+    width: 360px;
+    transform: translateX(100%);
+    box-shadow: none;
+  }
+}
+
 /* ============================================================
    PAGE HEADER + SECONDARY NAV (Settings, Admin)
    ============================================================ */

tests/persist.test.ts

@@ -0,0 +1,120 @@
+// @rstest-environment jsdom
+import { expect, test, beforeEach, rstest } from '@rstest/core';
+import {
+  loadQueueState,
+  loadPlayerState,
+  startPersistence,
+} from '../src/store/persist';
+import { queueInitialState, type QueueState } from '../src/store/slices/queue';
+import {
+  playerInitialState,
+  type PlayerState,
+} from '../src/store/slices/player';
+import {
+  upsertInstance,
+  setActiveInstanceId,
+  instanceStorage,
+} from '../src/config/instances';
+
+beforeEach(() => {
+  localStorage.clear();
+  const inst = upsertInstance('http://test.local');
+  setActiveInstanceId(inst.id);
+});
+
+const sampleQueue: QueueState = {
+  entries: [
+    {
+      trackId: 't1',
+      title: 'A',
+      artistName: 'X',
+      albumTitle: 'Alb',
+      durationMs: 1000,
+    },
+    {
+      trackId: 't2',
+      title: 'B',
+      artistName: 'Y',
+      albumTitle: 'Alb',
+      durationMs: 2000,
+    },
+  ],
+  currentIndex: 1,
+  source: 'album',
+  sourceId: 'alb-1',
+  sourceName: 'My Album',
+};
+
+test('loaders fall back to initial state with nothing persisted', () => {
+  expect(loadQueueState()).toEqual(queueInitialState);
+  expect(loadPlayerState()).toEqual(playerInitialState);
+});
+
+test('loadQueueState restores a persisted queue', () => {
+  instanceStorage.set('queue', JSON.stringify(sampleQueue));
+  expect(loadQueueState()).toEqual(sampleQueue);
+});
+
+test('loadQueueState guards a currentIndex past the entries array', () => {
+  instanceStorage.set(
+    'queue',
+    JSON.stringify({ ...sampleQueue, currentIndex: 99 }),
+  );
+  expect(loadQueueState().currentIndex).toBe(0);
+});
+
+test('loadPlayerState restores fields but never auto-resumes playback', () => {
+  instanceStorage.set(
+    'player',
+    JSON.stringify({
+      currentTrackId: 't2',
+      position: 42,
+      volume: 0.5,
+      muted: true,
+      repeat: 'all',
+      shuffle: true,
+      // a stale isPlaying:true must not survive a reload
+      isPlaying: true,
+    }),
+  );
+  const loaded = loadPlayerState();
+  expect(loaded.currentTrackId).toBe('t2');
+  expect(loaded.position).toBe(42);
+  expect(loaded.volume).toBe(0.5);
+  expect(loaded.repeat).toBe('all');
+  expect(loaded.isPlaying).toBe(false);
+});
+
+test('corrupt JSON falls back to initial state', () => {
+  instanceStorage.set('queue', '{not json');
+  expect(loadQueueState()).toEqual(queueInitialState);
+});
+
+test('startPersistence flushes changed state to storage after throttle', () => {
+  rstest.useFakeTimers();
+  let state = {
+    queue: queueInitialState,
+    player: playerInitialState,
+  } as { queue: QueueState; player: PlayerState };
+  let listener: (() => void) | null = null;
+  const store = {
+    getState: () => state as never,
+    subscribe: (l: () => void) => {
+      listener = l;
+      return () => {};
+    },
+  };
+
+  startPersistence(store);
+
+  // mutate + notify
+  state = { ...state, queue: sampleQueue };
+  listener!();
+  // nothing written before the throttle window elapses
+  expect(instanceStorage.get('queue')).toBeNull();
+
+  rstest.advanceTimersByTime(1000);
+  expect(JSON.parse(instanceStorage.get('queue')!).currentIndex).toBe(1);
+
+  rstest.useRealTimers();
+});

tests/rtkqPersist.test.ts

@@ -0,0 +1,99 @@
+// @rstest-environment jsdom
+import { expect, test, beforeEach, rstest } from '@rstest/core';
+import {
+  rehydrateApiCache,
+  startApiPersistence,
+} from '../src/store/rtkqPersist';
+import { REHYDRATE_API } from '../src/api/rehydrate';
+import {
+  upsertInstance,
+  setActiveInstanceId,
+  instanceStorage,
+} from '../src/config/instances';
+import type { RootState } from '../src/store/index';
+
+beforeEach(() => {
+  localStorage.clear();
+  const inst = upsertInstance('http://test.local');
+  setActiveInstanceId(inst.id);
+});
+
+function apiStateWith(queries: Record<string, unknown>) {
+  return {
+    api: { queries, mutations: {}, provided: {}, subscriptions: {}, config: {} },
+  } as unknown as RootState;
+}
+
+test('rehydrateApiCache dispatches nothing when no cache is stored', () => {
+  const dispatched: unknown[] = [];
+  rehydrateApiCache((a) => dispatched.push(a));
+  expect(dispatched).toHaveLength(0);
+});
+
+test('rehydrateApiCache replays a stored cache as a rehydrate action', () => {
+  instanceStorage.set(
+    'rtkq',
+    JSON.stringify({
+      queries: { 'getLibrary(undefined)': { status: 'fulfilled', data: [1] } },
+      mutations: {},
+    }),
+  );
+  const dispatched: Array<{ type: string; payload: unknown }> = [];
+  rehydrateApiCache((a) =>
+    dispatched.push(a as { type: string; payload: unknown }),
+  );
+  expect(dispatched).toHaveLength(1);
+  expect(dispatched[0].type).toBe(REHYDRATE_API);
+  expect(dispatched[0].payload).toMatchObject({
+    queries: { 'getLibrary(undefined)': { status: 'fulfilled' } },
+  });
+});
+
+test('rehydrate payload always carries `provided` (regression: RTKQ reads provided.tags)', () => {
+  // A snapshot persisted before `provided` existed must not crash RTKQ's
+  // invalidation slice, which does `Object.entries(provided.tags ?? {})`.
+  instanceStorage.set(
+    'rtkq',
+    JSON.stringify({
+      queries: { 'getLibrary(undefined)': { status: 'fulfilled', data: [] } },
+      mutations: {},
+    }),
+  );
+  const dispatched: Array<{ payload: { provided?: unknown } }> = [];
+  rehydrateApiCache((a) =>
+    dispatched.push(a as { payload: { provided?: unknown } }),
+  );
+  expect(dispatched[0].payload.provided).toEqual({ tags: {}, keys: {} });
+});
+
+test('startApiPersistence saves only fulfilled queries after throttle', () => {
+  rstest.useFakeTimers();
+  let state = apiStateWith({});
+  let listener: (() => void) | null = null;
+  const store = {
+    getState: () => state,
+    subscribe: (l: () => void) => {
+      listener = l;
+      return () => {};
+    },
+  };
+
+  startApiPersistence(store);
+
+  state = apiStateWith({
+    'getAlbums(undefined)': { status: 'fulfilled', data: ['a'] },
+    'getArtists(undefined)': { status: 'pending' },
+    'getTracks(undefined)': { status: 'rejected', error: 'boom' },
+  });
+  listener!();
+
+  // throttled — nothing yet
+  expect(instanceStorage.get('rtkq')).toBeNull();
+
+  rstest.advanceTimersByTime(2000);
+  const saved = JSON.parse(instanceStorage.get('rtkq')!);
+  expect(Object.keys(saved.queries)).toEqual(['getAlbums(undefined)']);
+  expect(saved.mutations).toEqual({});
+
+  rstest.useRealTimers();
+});

tests/sw-core.test.ts

@@ -0,0 +1,79 @@
+import { expect, test } from '@rstest/core';
+import {
+  trackIdFromUrl,
+  cacheKeyFor,
+  parseRangeHeader,
+  selectEvictions,
+} from '../public/sw-core.js';
+
+test('trackIdFromUrl extracts the content id from a stream URL', () => {
+  expect(
+    trackIdFromUrl('https://host/api/v1/stream/abc123?token=xyz'),
+  ).toBe('abc123');
+  expect(trackIdFromUrl('https://host/api/v1/library/albums')).toBeNull();
+});
+
+test('cacheKeyFor strips the token so the key is token-stable', () => {
+  const a = cacheKeyFor('https://host/api/v1/stream/t1?token=AAA');
+  const b = cacheKeyFor('https://host/api/v1/stream/t1?token=BBB');
+  expect(a).toBe(b);
+  expect(a).toBe('https://host/api/v1/stream/t1');
+});
+
+test('cacheKeyFor keeps different origins distinct', () => {
+  expect(cacheKeyFor('https://a/stream/t1?token=x')).not.toBe(
+    cacheKeyFor('https://b/stream/t1?token=x'),
+  );
+});
+
+test('parseRangeHeader: closed range', () => {
+  expect(parseRangeHeader('bytes=0-99', 1000)).toEqual({ start: 0, end: 99 });
+});
+
+test('parseRangeHeader: open-ended range clamps to size', () => {
+  expect(parseRangeHeader('bytes=500-', 1000)).toEqual({
+    start: 500,
+    end: 999,
+  });
+});
+
+test('parseRangeHeader: suffix range (last N bytes)', () => {
+  expect(parseRangeHeader('bytes=-200', 1000)).toEqual({
+    start: 800,
+    end: 999,
+  });
+});
+
+test('parseRangeHeader: end past size is clamped', () => {
+  expect(parseRangeHeader('bytes=900-5000', 1000)).toEqual({
+    start: 900,
+    end: 999,
+  });
+});
+
+test('parseRangeHeader: invalid / no range returns null', () => {
+  expect(parseRangeHeader('', 1000)).toBeNull();
+  expect(parseRangeHeader('items=0-1', 1000)).toBeNull();
+  expect(parseRangeHeader('bytes=500-100', 1000)).toBeNull();
+});
+
+test('selectEvictions: nothing evicted when under cap', () => {
+  const index = {
+    a: { size: 100, lastAccess: 1 },
+    b: { size: 100, lastAccess: 2 },
+  };
+  expect(selectEvictions(index, 100, 1000)).toEqual([]);
+});
+
+test('selectEvictions: evicts least-recently-used first until it fits', () => {
+  const index = {
+    a: { size: 400, lastAccess: 10 }, // oldest
+    b: { size: 400, lastAccess: 30 },
+    c: { size: 400, lastAccess: 20 },
+  };
+  // total 1200 + incoming 400 = 1600, cap 1000 → must free >=600.
+  // LRU order: a (10), c (20). Evict a (1200→800... wait incl incoming)
+  const evicted = selectEvictions(index, 400, 1000);
+  // total with incoming = 1600; evict a → 1200; evict c → 800 <= 1000.
+  expect(evicted).toEqual(['a', 'c']);
+});