feat(database): shape the library like files, and shrink the catalog

Plans 013 and 014, the album page that prompted them, and the smaller
fixes they turned up. Changelog, largest first.

## The local library is shaped like files, not like MusicBrainz

`audio_files` carries its own tags and points at `albums` and
`artists`; `file_genres` is the one real many-to-many. `recordings`,
`release_group_recordings`, `artist_credit`, `artist_credit_artist`,
`recording_genres`, `release_groups` and `release_to_rg` are gone from
the local side, and with them a six-way join in every read, a
`MIN(release_group_id)` subquery in eleven queries and a
first-credited-artist subquery in nine. Measured on a real 25,966-file
library, every many-to-many that model expressed was 1:1 in the data.

- Ownership is a file. `GetFilePathsByRecordingMBIDs`,
  `LibraryMBIDIndex.CheckMBIDs`, `collectLibraryEntities` and
  `pruneStaleLocalCrossReferences` all join `audio_files`, so the 812
  orphaned recordings, 216 release groups and 260 artists that library
  carried are now structurally impossible.
- One projection: every track query selects from the `track_metadata`
  view, one row type, one mapper. Nine hand-rolled copies had drifted
  far enough to report different years on different screens.
- `library_id = 0` means every library, so each list query exists once
  instead of scoped and unscoped with a branch at every call site.
- No migration chain. `sql/schemas/` is the one description of the
  shape; `sql/migrations/`, `applyMigrations` and `schema_migrations`
  are squashed away, along with the drift between them that had sqlc
  generating against a stale schema.
- `database.InsertTestTrack` is the one test seeder; twenty test files
  had been assembling the old FK chain each in its own order.

## The catalog stores its ids as bytes

`explore_index`'s three 36-char MBID columns and its entity-type text
are 16 raw bytes and a small integer. The table and its six indexes go
780 MB to 405 MB on a real 2,052,200-row catalog, which is why a fresh
install is ~0.6 GB rather than ~1.0 GB.

- `backend/explore/mbid.go` is the only place the encoding is known;
  everything above it speaks dashed strings.
- `CHECK(length(mbid) = 16)` makes a stringly write fail at the insert
  rather than silently returning no rows, since SQLite does not coerce
  between TEXT and BLOB.
- The importer asks the artifact what encoding it carries and converts
  on the way in, so the artifact already published keeps working and no
  format bump is needed.
- `indexRowColumns`/`scanIndexRow` replace four copies of a 22-column
  list, and `TestStoredEncodingRoundTrips` sweeps every read path.

## An album page that says how much of the album is yours

- One question, asked once: is there a file. `filePaths` is filled by a
  single batched lookup when the tracklist settles, and the badge, the
  Play count, the dimmed rows and every menu item read it — replacing
  four claims of decreasing confidence that could show a green tick on
  an album whose every action did nothing.
- Play, Play 7 of 12, or no play button at all.
- `total_tracks` on `explore_index` (~2 bytes over 400,677 release
  groups) and on `audio_files` from tags that have always carried it:
  a complete MBID-matched album now makes no catalog call at all, where
  it used to spend the most expensive request the app makes.
- A merged cluster shows the running order the most releases agree on,
  and the version list marks the release you own rather than standing a
  synthetic entry in for it.
- `AlbumReleasesFailed`: a slow fetch is no longer reported as a failed
  one by a 12-second timer.
- Rows not in the library are dimmed in place (with `aria-disabled`)
  instead of the owned ones wearing a green tick and a legend.

## Caches and cover art get ceilings

- Only the three tiers of a cover are stored; the full-resolution copy
  nothing rendered was 1,134 MB of a 1.4 GB covers directory.
- One artist portrait is downloaded and the rest are remembered as
  URLs — 4.1 GB of a 5.3 GB cache was candidates no code path reads.
- `browsedArtBudget` and `httpCacheBudget` bound what an age cannot:
  the same install held art for 5,770 artists in a 1,301-artist
  library.
- `OrphanedArtistImagesJob` joined a bare MBID onto a sharded
  directory, so it deleted the rows that were the only record of the
  files it left behind. `explore.ArtistImageDir` is that layout's one
  definition now.

## The autotag queue asks whether there is work

`tagging_items` was a row per album folder, not a queue, and no query
read the `tag_status` column that held the answer. The four queue
queries ask the files, which matters most where it is least visible:
`startPrefetch` was scoring every album in a tagged library against
MusicBrainz.

## Phantom playlist tracks resolve in place

An M3U8 imported before its files leaves phantom rows; they now match
by path and fall back to position, keep their place in the playlist
when resolved, and pair best-first so two phantoms cannot claim the
same file.

## Playing a track plays the list it is in

Double-click, and Play on a single row's menu, queue the list as
displayed with `startIndex` on that row — the album page and the track
list used to queue one track and discard the album around it. A
multi-row selection still plays exactly itself.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AfVYUVExXsx1nSWrXN8mAh

frontend/src/store/controllers/library-controller.ts

@@ -72,9 +72,9 @@ export class LibraryController implements ReactiveController {
     }
 
     async getAlbumsByArtist(
-        artistID: number,
+        artist: string,
     ): Promise<library.Album[]> {
-        return libraryStore.getAlbumsByArtist(artistID);
+        return libraryStore.getAlbumsByArtist(artist);
     }
 
     getAlbumsByArtistNameCached(

frontend/src/store/library-store.ts

@@ -1,15 +1,10 @@
 import { EventsOn } from '@runtime/runtime';
 import {
-    GetAllTracks,
-    GetAllAlbums,
-    GetAllArtists,
-    GetAllGenresWithCounts,
+    GetTracks,
+    GetAlbums,
+    GetArtists,
+    GetGenres,
     GetAlbumsByArtist,
-    GetAllTracksByLibrary,
-    GetAllAlbumsByLibrary,
-    GetAllArtistsByLibrary,
-    GetAllGenresWithCountsByLibrary,
-    GetAlbumsByArtistByLibrary,
     GetAllLibrariesWithTrackCounts,
 } from '@go/library/library.js';
 import type * as library from '@go/library/models.js';
@@ -228,11 +223,9 @@ class LibraryStore {
 
         if (pending) return pending;
 
-        const id = this.selectedLibraryIdValue;
-
         return this.track(
             'tracks',
-            list(id !== null ? GetAllTracksByLibrary(id) : GetAllTracks()),
+            list(GetTracks(this.libraryFilter())),
             (tracks) => {
                 this.tracks = tracks;
             },
@@ -249,11 +242,9 @@ class LibraryStore {
 
         if (pending) return pending;
 
-        const id = this.selectedLibraryIdValue;
-
         return this.track(
             'albums',
-            list(id !== null ? GetAllAlbumsByLibrary(id) : GetAllAlbums()),
+            list(GetAlbums(this.libraryFilter())),
             (albums) => {
                 this.albums = albums;
             },
@@ -270,11 +261,9 @@ class LibraryStore {
 
         if (pending) return pending;
 
-        const id = this.selectedLibraryIdValue;
-
         return this.track(
             'artists',
-            list(id !== null ? GetAllArtistsByLibrary(id) : GetAllArtists()),
+            list(GetArtists(this.libraryFilter())),
             (artists) => {
                 this.artists = artists;
             },
@@ -291,15 +280,9 @@ class LibraryStore {
 
         if (pending) return pending;
 
-        const id = this.selectedLibraryIdValue;
-
         return this.track(
             'genres',
-            list(
-                id !== null
-                    ? GetAllGenresWithCountsByLibrary(id)
-                    : GetAllGenresWithCounts(),
-            ),
+            list(GetGenres(this.libraryFilter())),
             (genres) => {
                 this.genres = genres;
             },
@@ -308,15 +291,21 @@ class LibraryStore {
     }
 
     async getAlbumsByArtist(
-        artistID: number,
+        artist: string,
     ): Promise<library.Album[]> {
-        const id = this.selectedLibraryIdValue;
+        return list(GetAlbumsByArtist(artist, this.libraryFilter()));
+    }
 
-        return list(
-            id !== null
-                ? GetAlbumsByArtistByLibrary(artistID, id)
-                : GetAlbumsByArtist(artistID),
-        );
+    /**
+     * The library id every backend query takes, where 0 means "all of
+     * them".
+     *
+     * Each of these used to be two bindings and a branch here, because
+     * the backend had a scoped and an unscoped query for every list.
+     * One query answers both now, so the branch is a `?? 0`.
+     */
+    libraryFilter(): number {
+        return this.selectedLibraryIdValue ?? 0;
     }
 
     /**