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

backend/library/filepaths_test.go

@@ -1,9 +1,9 @@
 package library
 
 import (
-	"database/sql"
 	"testing"
 
+	"yellowjacket/backend/database"
 	"yellowjacket/backend/database/sql/sqlcgen"
 )
 
@@ -32,22 +32,6 @@ func seedAlbumsAndGenres(t *testing.T, lib *Library) (albumIDs []int64, libraryI
 		t.Fatalf("create other library: %v", err)
 	}
 
-	ac, err := q.UpsertArtistCredit(ctx, "Test Artist")
-	if err != nil {
-		t.Fatalf("upsert artist credit: %v", err)
-	}
-
-	genreIDs := map[string]int64{}
-
-	for _, name := range []string{"Ambient", "Baroque"} {
-		g, err := q.UpsertGenre(ctx, name)
-		if err != nil {
-			t.Fatalf("upsert genre %s: %v", name, err)
-		}
-
-		genreIDs[name] = g.ID
-	}
-
 	// Two albums; the second lives in the other library so the
 	// library-scoped variants have something to exclude.
 	type spec struct {
@@ -66,63 +50,32 @@ func seedAlbumsAndGenres(t *testing.T, lib *Library) (albumIDs []int64, libraryI
 		{"Second", "B1", "/other/b1.mp3", other.ID, 1, 1, []string{"Baroque"}},
 	}
 
-	byAlbum := map[string]int64{}
+	seen := map[string]bool{}
 
 	for _, s := range specs {
-		rec, err := q.CreateRecordingFull(ctx, sqlcgen.CreateRecordingFullParams{
-			Name:           s.track,
-			ArtistCreditID: ac.ID,
+		database.InsertTestTrack(t, lib.db, database.TestTrack{
+			FilePath:    s.path,
+			Title:       s.track,
+			Artist:      "Test Artist",
+			Album:       s.album,
+			Genres:      s.genres,
+			TrackNumber: s.number,
+			DiscNumber:  s.disc,
+			LibraryID:   s.library,
+			LengthMs:    1000,
 		})
-		if err != nil {
-			t.Fatalf("create recording: %v", err)
-		}
 
-		rgID, ok := byAlbum[s.album]
+		if !seen[s.album] {
+			seen[s.album] = true
 
-		if !ok {
-			rg, err := q.UpsertReleaseGroup(ctx, sqlcgen.UpsertReleaseGroupParams{
-				Name:                s.album,
-				AlbumArtistCreditID: sql.NullInt64{Int64: ac.ID, Valid: true},
-			})
-			if err != nil {
-				t.Fatalf("upsert release group: %v", err)
+			var id int64
+			if err := lib.db.QueryRowWriter(
+				"SELECT id FROM albums WHERE name = ?", s.album,
+			).Scan(&id); err != nil {
+				t.Fatalf("album id for %q: %v", s.album, err)
 			}
 
-			rgID = rg.ID
-			byAlbum[s.album] = rgID
-			albumIDs = append(albumIDs, rgID)
-		}
-
-		if _, err := q.CreateReleaseGroupRecording(
-			ctx, sqlcgen.CreateReleaseGroupRecordingParams{
-				ReleaseGroupID: rgID,
-				RecordingID:    rec.ID,
-				TrackNumber:    sql.NullInt64{Int64: s.number, Valid: true},
-				DiscNumber:     sql.NullInt64{Int64: s.disc, Valid: true},
-			},
-		); err != nil {
-			t.Fatalf("link recording: %v", err)
-		}
-
-		if _, err := q.CreateAudioFile(ctx, sqlcgen.CreateAudioFileParams{
-			FilePath:           s.path,
-			LengthMilliseconds: 1000,
-			RecordingID:        rec.ID,
-			LibraryID:          s.library,
-			Basename:           s.track + ".mp3",
-		}); err != nil {
-			t.Fatalf("create audio file: %v", err)
-		}
-
-		for _, g := range s.genres {
-			if err := q.CreateRecordingGenre(
-				ctx, sqlcgen.CreateRecordingGenreParams{
-					RecordingID: rec.ID,
-					GenreID:     genreIDs[g],
-				},
-			); err != nil {
-				t.Fatalf("link genre: %v", err)
-			}
+			albumIDs = append(albumIDs, id)
 		}
 	}
 
@@ -237,9 +190,6 @@ func TestGetFilePathsByGenres_Empty(t *testing.T) {
 func seedRecordingMBIDs(t *testing.T, lib *Library) (tagged, shared string) {
 	t.Helper()
 
-	ctx := lib.ctx
-	q := lib.db.Queries
-
 	tagged = "11111111-1111-1111-1111-111111111111"
 	shared = "22222222-2222-2222-2222-222222222222"
 
@@ -249,22 +199,12 @@ func seedRecordingMBIDs(t *testing.T, lib *Library) (tagged, shared string) {
 		"/other/b1.mp3": shared,
 	}
 
-	files, err := q.GetAllAudioFiles(ctx)
-	if err != nil {
-		t.Fatalf("get audio files: %v", err)
-	}
-
-	for _, f := range files {
-		mbid, ok := byPath[f.FilePath]
-		if !ok {
-			continue
-		}
-
-		if err := q.SetRecordingMBID(ctx, sqlcgen.SetRecordingMBIDParams{
-			Mbid: sql.NullString{String: mbid, Valid: true},
-			ID:   f.RecordingID,
-		}); err != nil {
-			t.Fatalf("set recording mbid: %v", err)
+	for path, mbid := range byPath {
+		if _, err := lib.db.ExecContext(
+			"UPDATE audio_files SET recording_mbid = ? WHERE file_path = ?",
+			mbid, path,
+		); err != nil {
+			t.Fatalf("set recording mbid for %s: %v", path, err)
 		}
 	}