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/database/sql/queries/audio_files.sql

@@ -1,39 +1,60 @@
+-- Queries over audio_files and the track_metadata view above it.
+--
+-- Every query that returns "a track" selects from `track_metadata`,
+-- which is the one place the projection is defined.  The scoped and
+-- unscoped variants that used to be written twice are one query now:
+-- library_id 0 means "every library", and `(:id = 0 OR library_id = :id)`
+-- costs nothing measurable (23 ms vs 21 ms over 26k rows) because these
+-- queries scan either way.
+
+-- ---------------------------------------------------------------------
+-- Writes
+-- ---------------------------------------------------------------------
+
 -- name: CreateAudioFile :one
-INSERT INTO audio_files (file_path, length_milliseconds, file_type_id, recording_id, sample_rate, bit_depth, channels, bitrate, file_size, basename, library_id) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
-RETURNING *;
-
--- name: CreateAudioFileWithGroupKey :one
 INSERT INTO audio_files (
-  file_path, length_milliseconds, file_type_id, recording_id,
-  sample_rate, bit_depth, channels, bitrate, file_size, basename,
-  library_id, group_key, tag_status, modified_at
-) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+  file_path, library_id, file_type_id,
+  length_milliseconds, sample_rate, bit_depth, channels, bitrate, file_size,
+  title, artist_credit, artist_id, album_id,
+  track_number, disc_number, total_tracks, year, composer, comment,
+  recording_mbid, basename, group_key, modified_at, tag_status
+) VALUES (
+  ?, ?, ?,
+  ?, ?, ?, ?, ?, ?,
+  ?, ?, ?, ?,
+  ?, ?, ?, ?, ?, ?,
+  ?, ?, ?, ?, ?
+)
 RETURNING *;
 
--- name: GetAudioFileGroupKey :one
-SELECT group_key FROM audio_files
-WHERE id = ? LIMIT 1;
+-- name: UpdateAudioFileTags :exec
+-- A rescan of a file whose mtime moved: the tags are re-read and
+-- written over the same row.  Under the old schema this created a
+-- *new* recording and repointed the file at it, abandoning the old one
+-- -- which is where 812 orphaned rows and every phantom "you own this"
+-- came from.  There is nothing to orphan now.
+UPDATE audio_files
+SET title = ?, artist_credit = ?, artist_id = ?, album_id = ?,
+    track_number = ?, disc_number = ?, total_tracks = ?, year = ?,
+    composer = ?, comment = ?, recording_mbid = ?,
+    sample_rate = ?, bit_depth = ?, channels = ?, bitrate = ?,
+    file_size = ?, length_milliseconds = ?, modified_at = ?
+WHERE id = ?;
 
 -- name: SetAudioFileGroupKey :exec
 UPDATE audio_files SET group_key = ? WHERE id = ?;
 
--- name: GetAudioFile :one
-SELECT * FROM audio_files 
-WHERE id = ? LIMIT 1;
-
--- name: GetAudioFileByPath :one
-SELECT * FROM audio_files
-WHERE file_path = ? LIMIT 1;
-
--- name: UpdateAudioFile :exec
-UPDATE audio_files 
-SET file_path = ?, length_milliseconds = ?, file_type_id = ?, recording_id = ?, sample_rate = ?, bit_depth = ?, channels = ?, bitrate = ?, file_size = ?, basename = ?
-WHERE id = ?;
-
--- name: UpdateAudioFileRecording :exec
+-- name: PromoteAudioFileTagStatusIfUntagged :exec
+-- A rescan re-reads the tags of a file whose mtime moved, so a file
+-- another tagger stamped with MBIDs since import arrives here still
+-- carrying the 'untagged' status it was created with (only the insert
+-- path sets it).  Promote it the same way saveAudioFile does.
+-- Guarded on 'untagged' so it cannot overwrite a deliberate
+-- 'user_skipped_permanent', and so a file losing its MBIDs is left
+-- alone -- demotion is the scan's judgement, not this statement's.
 UPDATE audio_files
-SET recording_id = ?, sample_rate = ?, bit_depth = ?, channels = ?, bitrate = ?, file_size = ?, length_milliseconds = ?, modified_at = ?
-WHERE id = ?;
+SET tag_status = 'user_confirmed'
+WHERE id = ? AND tag_status = 'untagged';
 
 -- name: UpdateAudioFileStat :exec
 -- Records the on-disk mtime/size without re-reading tags.  Used to
@@ -43,307 +64,146 @@ UPDATE audio_files
 SET modified_at = ?, file_size = ?
 WHERE id = ?;
 
+-- name: SetAudioFileRecordingMBID :exec
+UPDATE audio_files SET recording_mbid = ? WHERE id = ?;
+
+-- name: DeleteAudioFile :exec
+DELETE FROM audio_files WHERE id = ?;
+
+-- name: DeleteAllAudioFiles :exec
+DELETE FROM audio_files;
+
+-- ---------------------------------------------------------------------
+-- Reads: the file row itself
+-- ---------------------------------------------------------------------
+
+-- name: GetAudioFile :one
+SELECT * FROM audio_files WHERE id = ? LIMIT 1;
+
+-- name: GetAudioFileByPath :one
+SELECT * FROM audio_files WHERE file_path = ? LIMIT 1;
+
+-- name: GetAudioFileGroupKey :one
+SELECT group_key FROM audio_files WHERE id = ? LIMIT 1;
+
+-- name: GetAllAudioFilePaths :many
+SELECT id, file_path FROM audio_files;
+
+-- name: GetAudioFilesByPaths :many
+SELECT id, library_id, file_path, group_key FROM audio_files
+WHERE file_path IN (sqlc.slice('paths'));
+
+-- name: GetRandomAudioFilePath :one
+SELECT file_path FROM audio_files ORDER BY RANDOM() LIMIT 1;
+
+-- name: CountAudioFiles :one
+SELECT COUNT(*) AS count FROM audio_files
+WHERE library_id = COALESCE(NULLIF(CAST(sqlc.arg(library_id) AS INTEGER), 0), library_id);
+
 -- name: GetLibraryMaxModifiedAt :one
 -- Newest recorded mtime in a library, for the startup soft scan.  0 when
 -- the library is empty or no row has a baseline yet.
 SELECT CAST(COALESCE(MAX(modified_at), 0) AS INTEGER) FROM audio_files
 WHERE library_id = ?;
 
--- name: DeleteAudioFile :exec
-DELETE FROM audio_files 
-WHERE id = ?;
+-- ---------------------------------------------------------------------
+-- Reads: tracks
+-- ---------------------------------------------------------------------
 
--- name: CountAudioFiles :one
-SELECT count(*) FROM audio_files;
+-- name: GetTracks :many
+SELECT * FROM track_metadata
+WHERE library_id = COALESCE(NULLIF(CAST(sqlc.arg(library_id) AS INTEGER), 0), library_id);
 
--- name: GetRandomAudioFilePath :one
-SELECT file_path FROM audio_files
-ORDER BY RANDOM()
-LIMIT 1;
+-- name: GetTrackByPath :one
+SELECT * FROM track_metadata WHERE file_path = ? LIMIT 1;
 
--- name: GetAllAudioFiles :many
-SELECT * FROM audio_files;
+-- name: GetTracksByAlbum :many
+SELECT * FROM track_metadata
+WHERE album_id = sqlc.arg(album_id)
+  AND library_id = COALESCE(NULLIF(CAST(sqlc.arg(library_id) AS INTEGER), 0), library_id)
+ORDER BY disc_number, track_number;
 
--- name: GetAllAudioFilePaths :many
-SELECT id, file_path FROM audio_files;
-
--- name: GetAudioFilesNeedingMetadata :many
-SELECT * FROM audio_files
-WHERE recording_id = 0;
-
--- name: GetAllAudioFilesWithArtist :many
-SELECT 
-    af.id,
-    af.file_path,
-    af.length_milliseconds,
-    af.file_type_id,
-    af.recording_id,
-    COALESCE(ac.text, '') AS artist_name,
-    COALESCE(r.name, '') AS title
-FROM audio_files af
-JOIN recordings r ON af.recording_id = r.id
-JOIN artist_credit ac ON r.artist_credit_id = ac.id;
-
--- name: GetTrackMetadataByPath :one
-SELECT 
-    af.file_path,
-    af.length_milliseconds,
-    COALESCE(r.name, '') AS title,
-    COALESCE(ac.text, '') AS artist,
-    COALESCE(rg.name, '') AS album,
-    COALESCE(ca.file_path, '') AS cover_art_path,
-    COALESCE(a.mbid, '') AS artist_mbid,
-    COALESCE(rg.mbid, '') AS release_group_mbid,
-    COALESCE(r.mbid, '') AS recording_mbid
-FROM audio_files af
-LEFT JOIN recordings r ON af.recording_id = r.id
-LEFT JOIN artist_credit ac ON r.artist_credit_id = ac.id
-LEFT JOIN artist_credit_artist aca ON aca.credit_id = ac.id
-LEFT JOIN artists a ON a.id = aca.artist_id
-LEFT JOIN release_group_recordings rgr ON r.id = rgr.recording_id
-LEFT JOIN release_groups rg ON rgr.release_group_id = rg.id
-LEFT JOIN cover_art ca ON rg.cover_art_id = ca.id
-WHERE af.file_path = ?
-LIMIT 1;
-
--- name: GetAllTracksWithFullMetadata :many
-SELECT
-    af.file_path,
-    af.length_milliseconds,
-    COALESCE(r.name, '') AS title,
-    COALESCE(ac.text, '') AS artist_name,
-    r.track_number,
-    r.disc_number,
-    COALESCE(rg.name, '') AS album,
-    CAST(COALESCE(
-        (SELECT GROUP_CONCAT(g.name, '||')
-         FROM recording_genres rg_sub
-         JOIN genres g ON rg_sub.genre_id = g.id
-         WHERE rg_sub.recording_id = r.id),
-        ''
-    ) AS TEXT) AS genre,
-    COALESCE(r.year, 0) AS year,
-    COALESCE(r.composer, '') AS composer,
-    COALESCE(ft.extension, '') AS file_type,
-    af.sample_rate,
-    af.bit_depth,
-    af.channels,
-    af.bitrate,
-    af.file_size,
-    af.play_count,
-    af.last_played,
-    COALESCE(ca.file_path, '') AS cover_art_path,
-    COALESCE(a.mbid, '') AS artist_mbid,
-    COALESCE(rg.mbid, '') AS release_group_mbid,
-    COALESCE(r.mbid, '') AS recording_mbid
-FROM audio_files af
-JOIN recordings r ON af.recording_id = r.id
-JOIN artist_credit ac ON r.artist_credit_id = ac.id
-LEFT JOIN artist_credit_artist aca ON aca.credit_id = ac.id
-LEFT JOIN artists a ON a.id = aca.artist_id
-LEFT JOIN release_group_recordings rgr ON r.id = rgr.recording_id
-LEFT JOIN release_groups rg ON rgr.release_group_id = rg.id
-LEFT JOIN cover_art ca ON rg.cover_art_id = ca.id
-LEFT JOIN file_types ft ON af.file_type_id = ft.id;
-
--- name: SearchAudioFilesByBasename :many
-SELECT
-    af.file_path,
-    af.length_milliseconds,
-    COALESCE(r.name, '') AS title,
-    COALESCE(ac.text, '') AS artist,
-    COALESCE(rg.name, '') AS album
-FROM audio_files af
-LEFT JOIN recordings r ON af.recording_id = r.id
-LEFT JOIN artist_credit ac ON r.artist_credit_id = ac.id
-LEFT JOIN (
-    SELECT recording_id, MIN(release_group_id) AS release_group_id
-    FROM release_group_recordings
-    GROUP BY recording_id
-) rgr ON r.id = rgr.recording_id
-LEFT JOIN release_groups rg ON rgr.release_group_id = rg.id
-WHERE af.basename = ?
-LIMIT ?;
+-- name: GetTracksByGenre :many
+SELECT tm.* FROM track_metadata tm
+JOIN file_genres fg ON fg.audio_file_id = tm.id
+JOIN genres g ON g.id = fg.genre_id
+WHERE g.name = sqlc.arg(genre)
+  AND tm.library_id = COALESCE(NULLIF(CAST(sqlc.arg(library_id) AS INTEGER), 0), tm.library_id);
 
 -- name: LookupTrackMetaByPaths :many
-SELECT id, file_path, title, artist_name, album, cover_art_path, artist_mbid, release_group_mbid, recording_mbid
+SELECT id, file_path, title, artist_name, album, cover_art_path,
+       artist_mbid, release_group_mbid, recording_mbid
 FROM track_metadata
 WHERE file_path IN (sqlc.slice('paths'));
 
--- name: GetAudioFilesByLibrary :many
-SELECT * FROM audio_files WHERE library_id = ?;
+-- name: SearchTracksByBasename :many
+SELECT id, file_path, length_milliseconds, title, artist_name, album
+FROM track_metadata
+WHERE file_path IN (
+    SELECT file_path FROM audio_files WHERE basename = sqlc.arg(basename)
+)
+LIMIT sqlc.arg(lim);
 
--- name: CountAudioFilesByLibrary :one
-SELECT COUNT(*) AS count FROM audio_files WHERE library_id = ?;
+-- ---------------------------------------------------------------------
+-- Reads: file paths, grouped by whatever the caller asked about
+-- ---------------------------------------------------------------------
+-- These answer "what can I play" and they all ask audio_files, because
+-- that is the only table whose rows are files.  Grouped rather than
+-- flattened because the caller owns the order.
 
--- name: DeleteAllAudioFiles :exec
-DELETE FROM audio_files;
-
--- name: GetAllTracksWithFullMetadataByLibrary :many
-SELECT
-    af.file_path,
-    af.length_milliseconds,
-    COALESCE(r.name, '') AS title,
-    COALESCE(ac.text, '') AS artist_name,
-    r.track_number,
-    r.disc_number,
-    COALESCE(rg.name, '') AS album,
-    CAST(COALESCE(
-        (SELECT GROUP_CONCAT(g.name, '||')
-         FROM recording_genres rg_sub
-         JOIN genres g ON rg_sub.genre_id = g.id
-         WHERE rg_sub.recording_id = r.id),
-        ''
-    ) AS TEXT) AS genre,
-    COALESCE(r.year, 0) AS year,
-    COALESCE(r.composer, '') AS composer,
-    COALESCE(ft.extension, '') AS file_type,
-    af.sample_rate,
-    af.bit_depth,
-    af.channels,
-    af.bitrate,
-    af.file_size,
-    af.play_count,
-    af.last_played,
-    COALESCE(ca.file_path, '') AS cover_art_path,
-    COALESCE(a.mbid, '') AS artist_mbid,
-    COALESCE(rg.mbid, '') AS release_group_mbid,
-    COALESCE(r.mbid, '') AS recording_mbid
-FROM audio_files af
-JOIN recordings r ON af.recording_id = r.id
-JOIN artist_credit ac ON r.artist_credit_id = ac.id
-LEFT JOIN artist_credit_artist aca ON aca.credit_id = ac.id
-LEFT JOIN artists a ON a.id = aca.artist_id
-LEFT JOIN release_group_recordings rgr ON r.id = rgr.recording_id
-LEFT JOIN release_groups rg ON rgr.release_group_id = rg.id
-LEFT JOIN cover_art ca ON rg.cover_art_id = ca.id
-LEFT JOIN file_types ft ON af.file_type_id = ft.id
-WHERE af.library_id = ?;
-
--- name: GetAudioFilesByReleaseGroup :many
-SELECT
-    af.file_path,
-    af.length_milliseconds,
-    COALESCE(r.name, '') AS title,
-    COALESCE(ac.text, '') AS artist_name,
-    rgr.track_number,
-    rgr.disc_number,
-    COALESCE(rg.name, '') AS album,
-    CAST(COALESCE(
-        (SELECT GROUP_CONCAT(g.name, '||')
-         FROM recording_genres rg_sub
-         JOIN genres g ON rg_sub.genre_id = g.id
-         WHERE rg_sub.recording_id = r.id),
-        ''
-    ) AS TEXT) AS genre,
-    COALESCE(r.year, 0) AS year,
-    COALESCE(r.composer, '') AS composer,
-    COALESCE(ft.extension, '') AS file_type,
-    af.sample_rate,
-    af.bit_depth,
-    af.channels,
-    af.bitrate,
-    af.file_size,
-    COALESCE(a.mbid, '') AS artist_mbid,
-    COALESCE(rg.mbid, '') AS release_group_mbid,
-    COALESCE(r.mbid, '') AS recording_mbid
-FROM release_group_recordings rgr
-JOIN recordings r ON rgr.recording_id = r.id
-JOIN audio_files af ON af.recording_id = r.id
-LEFT JOIN artist_credit ac ON r.artist_credit_id = ac.id
-LEFT JOIN artist_credit_artist aca ON aca.credit_id = ac.id
-LEFT JOIN artists a ON a.id = aca.artist_id
-LEFT JOIN release_groups rg ON rgr.release_group_id = rg.id
-LEFT JOIN file_types ft ON af.file_type_id = ft.id
-WHERE rgr.release_group_id = ?
-ORDER BY rgr.disc_number, rgr.track_number;
-
--- name: GetAudioFilesByReleaseGroupByLibrary :many
-SELECT
-    af.file_path,
-    af.length_milliseconds,
-    COALESCE(r.name, '') AS title,
-    COALESCE(ac.text, '') AS artist_name,
-    rgr.track_number,
-    rgr.disc_number,
-    COALESCE(rg.name, '') AS album,
-    CAST(COALESCE(
-        (SELECT GROUP_CONCAT(g.name, '||')
-         FROM recording_genres rg_sub
-         JOIN genres g ON rg_sub.genre_id = g.id
-         WHERE rg_sub.recording_id = r.id),
-        ''
-    ) AS TEXT) AS genre,
-    COALESCE(r.year, 0) AS year,
-    COALESCE(r.composer, '') AS composer,
-    COALESCE(ft.extension, '') AS file_type,
-    af.sample_rate,
-    af.bit_depth,
-    af.channels,
-    af.bitrate,
-    af.file_size,
-    COALESCE(a.mbid, '') AS artist_mbid,
-    COALESCE(rg.mbid, '') AS release_group_mbid,
-    COALESCE(r.mbid, '') AS recording_mbid
-FROM release_group_recordings rgr
-JOIN recordings r ON rgr.recording_id = r.id
-JOIN audio_files af ON af.recording_id = r.id
-LEFT JOIN artist_credit ac ON r.artist_credit_id = ac.id
-LEFT JOIN artist_credit_artist aca ON aca.credit_id = ac.id
-LEFT JOIN artists a ON a.id = aca.artist_id
-LEFT JOIN release_groups rg ON rgr.release_group_id = rg.id
-LEFT JOIN file_types ft ON af.file_type_id = ft.id
-WHERE rgr.release_group_id = ? AND af.library_id = ?
-ORDER BY rgr.disc_number, rgr.track_number;
-
--- "Play this artist" and "play these albums" wanted file paths and asked
--- for whole track rows to get them, one round trip per album (perf.m2).
--- These answer the same question in one query and carry only what the
--- caller uses; the release group id comes back so the caller can keep
--- its own album ordering.
-
--- name: GetFilePathsByReleaseGroups :many
-SELECT rgr.release_group_id, af.file_path
-FROM release_group_recordings rgr
-JOIN recordings r ON rgr.recording_id = r.id
-JOIN audio_files af ON af.recording_id = r.id
-WHERE rgr.release_group_id IN (sqlc.slice('release_group_ids'))
-ORDER BY rgr.disc_number, rgr.track_number;
-
--- name: GetFilePathsByReleaseGroupsByLibrary :many
-SELECT rgr.release_group_id, af.file_path
-FROM release_group_recordings rgr
-JOIN recordings r ON rgr.recording_id = r.id
-JOIN audio_files af ON af.recording_id = r.id
-WHERE rgr.release_group_id IN (sqlc.slice('release_group_ids'))
-  AND af.library_id = ?
-ORDER BY rgr.disc_number, rgr.track_number;
-
--- Same shape again, keyed on recording MBID, for the catalog side.
--- An Explore album page knows which of its tracks the user owns only
--- as a set of recording MBIDs -- that is exactly how the backend
--- decides `inLibrary` (markReleasesInLibrary -> CheckMBIDs) -- and
--- MBTrack.LocalID is declared but never written by anything, so there
--- is no id to ask by. Grouped by MBID because a recording can have
--- more than one file (the duplicate fixtures are precisely that) and
--- because the caller owns the order: the tracklist's, not the
--- database's.
+-- name: GetFilePathsByAlbums :many
+-- The library filter is applied in Go rather than here: sqlc numbers a
+-- named parameter (?2) but expands a slice into N placeholders, so the
+-- two together bind the wrong values - GetFilePathsByAlbums([1,2], 0)
+-- read album id 2 as the library id.  Returning library_id and
+-- filtering the (small) result is the version that cannot be wrong.
+SELECT album_id, library_id, file_path FROM audio_files
+WHERE album_id IN (sqlc.slice('album_ids'))
+ORDER BY disc_number, track_number;
 
 -- name: GetFilePathsByRecordingMBIDs :many
-SELECT r.mbid AS recording_mbid, af.file_path
-FROM recordings r
-JOIN audio_files af ON af.recording_id = r.id
-WHERE r.mbid IN (sqlc.slice('mbids'))
-ORDER BY af.file_path;
+-- The ownership question in its only honest form: which of these
+-- catalog recordings has a *file* behind it.  Asked of audio_files, so
+-- a metadata row with no file cannot answer yes.
+SELECT recording_mbid, library_id, file_path FROM audio_files
+WHERE recording_mbid IN (sqlc.slice('mbids'))
+ORDER BY file_path;
 
--- name: GetFilePathsByRecordingMBIDsByLibrary :many
-SELECT r.mbid AS recording_mbid, af.file_path
-FROM recordings r
-JOIN audio_files af ON af.recording_id = r.id
-WHERE r.mbid IN (sqlc.slice('mbids'))
-  AND af.library_id = ?
-ORDER BY af.file_path;
+-- name: GetFilePathsByGenres :many
+SELECT g.name AS genre, af.library_id, af.file_path
+FROM audio_files af
+JOIN file_genres fg ON fg.audio_file_id = af.id
+JOIN genres g ON g.id = fg.genre_id
+WHERE g.name IN (sqlc.slice('genres'))
+ORDER BY af.disc_number, af.track_number;
 
--- name: GetAudioFilesByPaths :many
-SELECT id, library_id, file_path, group_key FROM audio_files
-WHERE file_path IN (sqlc.slice('paths'));
+-- name: GetFilePathsByArtistMBID :many
+SELECT DISTINCT af.file_path
+FROM audio_files af
+JOIN artists a ON a.id = af.artist_id
+WHERE a.mbid = ?;
+
+-- ---------------------------------------------------------------------
+-- Ownership, asked in bulk
+-- ---------------------------------------------------------------------
+
+-- name: OwnedRecordingMBIDs :many
+-- Which of these recording MBIDs are actually in the library.  This is
+-- what marks a catalog tracklist owned; it used to be
+-- `SELECT mbid FROM recordings`, which answered yes for 129 tracks in a
+-- real library that had no file at all.
+SELECT DISTINCT recording_mbid FROM audio_files
+WHERE recording_mbid IN (sqlc.slice('mbids'));
+
+-- name: OwnedAlbumMBIDs :many
+SELECT DISTINCT al.mbid FROM albums al
+JOIN audio_files af ON af.album_id = al.id
+WHERE al.mbid IN (sqlc.slice('mbids'));
+
+-- name: OwnedArtistMBIDs :many
+SELECT DISTINCT a.mbid FROM artists a
+JOIN audio_files af ON af.artist_id = a.id
+WHERE a.mbid IN (sqlc.slice('mbids'));
+
+-- name: GetAudioFilesInLibrary :many
+SELECT * FROM audio_files WHERE library_id = ?;