feat: implement 1B domain entities/repos + 1H library API routes

1B — domain layer:
- New entities: Album, Playlist, Like, PlayHistoryEntry
- Track entity extended with album_id, genre, year fields
- New protocols: AlbumRepository, PlaylistRepository, LikeRepository, HistoryRepository
- ArtistRepository / TrackRepository protocols extended (list, count, update, get_many, etc.)
- New repos: SqlAlchemyAlbum/Playlist/Like/HistoryRepository
- Artist and track repos updated to match extended protocols

1H — library API:
- Pagination: PagedResponse[T] generic, offset-based, limit default 50 max 200
- Schemas: TrackOut, AlbumOut, ArtistOut, PlaylistOut/Create/Update,
  LikeEvent/State, HistoryIn/Out, LibrarySearchResponse
- GET/PATCH/DELETE /tracks with filters, sort, pagination
- GET /albums, /albums/{id}, /albums/{id}/tracks
- GET /artists, /artists/{id}, /artists/{id}/albums, /artists/{id}/tracks
- GET /search/library (ILIKE across tracks/albums/artists)
- Full /playlists CRUD + track add/remove (append-only version bump)
- POST /likes (append-only event log), GET /likes, GET /likes/state
- POST /history (scrobble), GET /history
- deps.py: TrackRepoDep, ArtistRepoDep, AlbumRepoDep, PlaylistRepoDep,
  LikeRepoDep, HistoryRepoDep

ruff ✅  mypy ✅  pytest 45/45 ✅

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/api/v1/search.py

@@ -2,14 +2,77 @@
 
 from typing import Any
 
-from fastapi import APIRouter
+from fastapi import APIRouter, Query
+
+from app.api.deps import AlbumRepoDep, ArtistRepoDep, CurrentUser, TrackRepoDep
+from app.api.schemas.album import AlbumOut
+from app.api.schemas.artist import ArtistOut
+from app.api.schemas.search import LibrarySearchResponse
+from app.api.schemas.track import TrackOut
+from app.api.v1.albums import _build_album_out
+from app.api.v1.tracks import _build_track_out
 
 router = APIRouter(prefix="/search", tags=["search"])
 
 
 @router.get("")
-async def search() -> Any: ...
+async def search(_: CurrentUser) -> Any: ...
 
 
 @router.get("/library")
-async def search_library() -> Any: ...
+async def search_library(
+    track_repo: TrackRepoDep,
+    artist_repo: ArtistRepoDep,
+    album_repo: AlbumRepoDep,
+    _: CurrentUser,
+    q: str = Query(min_length=1),
+    types: str = Query(default="tracks,albums,artists"),
+    limit: int = Query(20, ge=1, le=100),
+) -> LibrarySearchResponse:
+    requested = {t.strip() for t in types.split(",")}
+
+    tracks_out: list[TrackOut] = []
+    albums_out: list[AlbumOut] = []
+    artists_out: list[ArtistOut] = []
+
+    if "tracks" in requested:
+        tracks = await track_repo.list(
+            artist_id=None,
+            album_id=None,
+            q=q,
+            sort_by="title",
+            order="asc",
+            limit=limit,
+            offset=0,
+        )
+        if tracks:
+            artist_ids = list({t.artist_id for t in tracks})
+            album_ids = list({t.album_id for t in tracks if t.album_id is not None})
+            artists_map = {a.id: a for a in await artist_repo.get_many(artist_ids)}
+            albums_map = {a.id: a for a in await album_repo.get_many(album_ids)}
+            tracks_out = await _build_track_out(tracks, artists_map, albums_map)
+
+    if "albums" in requested:
+        albums = await album_repo.list(artist_id=None, q=q, limit=limit, offset=0)
+        if albums:
+            artist_ids = list({a.artist_id for a in albums})
+            artists_map = {a.id: a for a in await artist_repo.get_many(artist_ids)}
+            track_counts = await album_repo.track_count_many([a.id for a in albums])
+            albums_out = await _build_album_out(albums, artists_map, track_counts)
+
+    if "artists" in requested:
+        raw_artists = await artist_repo.list(q=q, limit=limit, offset=0)
+        for a in raw_artists:
+            album_cnt = await artist_repo.album_count(a.id)
+            track_cnt = await artist_repo.track_count(a.id)
+            artists_out.append(
+                ArtistOut(
+                    id=a.id,
+                    name=a.name,
+                    album_count=album_cnt,
+                    track_count=track_cnt,
+                    created_at=a.created_at,
+                )
+            )
+
+    return LibrarySearchResponse(tracks=tracks_out, albums=albums_out, artists=artists_out)