Replace the scaffold Placeholder with a real artist page wired to the
existing `/artists/{id}` (+ `/albums`, `/tracks`) endpoints: header with
procedural avatar / counts / "Play all" (queues with source=artist),
discography grid (cards → album detail), and the full track list. All
three list states per async section.
Also make the Library artists-tab rows clickable → `/artists/:id`,
closing the previous navigation dead-end.
i18n: new `artist.*` block (en + ru).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Senko-san
45a624b642