drop the songs tab and the whole-library song queue

docs/architecture.md

@@ -70,7 +70,7 @@ Compose UI  ->  ViewModel  ->  Repository  ->  MusicSource (remote, Subsonic)
 
 ## UI shell
 
-The library is one `LibraryScreen` with a pinned top bar: the current section as the title, a custom row of icon buttons (Albums, Artists, Songs, Playlists) on the left, and Sync and Settings icon actions on the right. The selected section is drawn as a filled box in the content colour with the icon inverted, like the Flutter app — this is a hand-rolled row, not Material `TabRow` (no underline indicator). Icons use the Material rounded variants. Tabs switch the content in place; album and playlist rows push a detail screen, and Settings is pushed from the top bar. The sync action doubles as the progress indicator while a sync runs. There is no bottom navigation. A mini player sits above the navigation bar across every screen whenever a track is loaded. It is a permanent part of the app shell (the screens above it consume the navigation-bar inset so nothing is padded twice); the Now Playing screen slides up over the whole shell as an overlay rather than being a nav destination, so the mini player never re-lays out during the transition.
+The library is one `LibraryScreen` with a pinned top bar: the current section as the title, a custom row of icon buttons (Albums, Artists, Playlists) on the left, and Sync and Settings icon actions on the right. The selected section is drawn as a filled box in the content colour with the icon inverted, like the Flutter app — this is a hand-rolled row, not Material `TabRow` (no underline indicator). Icons use the Material rounded variants. Tabs switch the content in place; album and playlist rows push a detail screen, and Settings is pushed from the top bar. The sync action doubles as the progress indicator while a sync runs. There is no bottom navigation. A mini player sits above the navigation bar across every screen whenever a track is loaded. It is a permanent part of the app shell (the screens above it consume the navigation-bar inset so nothing is padded twice); the Now Playing screen slides up over the whole shell as an overlay rather than being a nav destination, so the mini player never re-lays out during the transition.
 
 The Albums tab is a three-column grid of covers only — a later preference will toggle captions, and sorting will hang off a FAB, so Settings only manages servers and neither shows sort nor sync controls.
 
@@ -100,7 +100,7 @@ UI and playback preferences live in DataStore (`user_prefs`), not in SQLite: the
 
 Every schema version step ships a hand-written `Migration` (`data/db/Migrations.kt`), and there is no destructive fallback, so an upgrade never silently wipes the local mirror. The exported schemas under `app/schemas/` are the source of truth for the migration SQL, and `MigrationsTest` runs each step against a real SQLite connection and asserts the resulting tables, columns and indices.
 
-Library screens page over Room with `PagingSource<Int, T>` queries, ordering by a sort chosen in preferences (name, artist, year, recently added). Paging is local, but it keeps memory bounded on large libraries and lets a huge song or playlist list render incrementally. Room 3 requires `@DaoReturnTypeConverters(PagingSourceDaoReturnTypeConverter::class)` on the DAO for this.
+Library screens page over Room with `PagingSource<Int, T>` queries, ordering by a sort chosen in preferences (name, artist, year, recently added). Paging is local, but it keeps memory bounded on large libraries and lets a huge playlist render incrementally. Room 3 requires `@DaoReturnTypeConverters(PagingSourceDaoReturnTypeConverter::class)` on the DAO for this.
 
 Song rows show the album's cover art, fetched by joining `songs` to `albums` into a `SongListItem` rather than storing cover art on the song: some servers return a distinct cover ID per track, and keeping those would fragment the image cache for no visual gain. Artists show their image cropped to a circle.
 
@@ -118,7 +118,7 @@ Sync is not atomic. Each batch commits on its own, so a failure leaves the batch
 
 ## Search
 
-Search is a case-insensitive substring filter on the library queries (`instr(lower(column), lower(:search)) > 0` in `LibraryDao`), scoped to the active tab and with the matching rows ordered by the tab's sort. There is no separate search index; the filter runs directly against the library tables. An FTS5 trigram shadow table was trialled and dropped: it was wired to a separate search screen that went unused, and it indexed only `title`, so it did not cover the per-field substring the inline filter does. The decision is reversible if infix search over a very large library ever needs an index, because `tokenize='trigram'` is the only SQLite built-in that can index an arbitrary substring match. A revival must index every field the filter scans (`title`/`artist`/`album` for songs, `name`/`albumArtist` for albums, `name` for artists and playlists), be kept current incrementally per sync batch rather than cleared and rebuilt, and accept a three-character minimum (shorter queries fall back to the scan); sorting and paging would still come from the normal indexed library queries.
+Search is a case-insensitive substring filter on the library queries (`instr(lower(column), lower(:search)) > 0` in `LibraryDao`), scoped to the active tab and with the matching rows ordered by the tab's sort. There is no separate search index; the filter runs directly against the library tables. An FTS5 trigram shadow table was trialled and dropped: it was wired to a separate search screen that went unused, and it indexed only `title`, so it did not cover the per-field substring the inline filter does. The decision is reversible if infix search over a very large library ever needs an index, because `tokenize='trigram'` is the only SQLite built-in that can index an arbitrary substring match. A revival must index every field the filter scans (`name`/`albumArtist` for albums, `name` for artists and playlists), be kept current incrementally per sync batch rather than cleared and rebuilt, and accept a three-character minimum (shorter queries fall back to the scan); sorting and paging would still come from the normal indexed library queries.
 
 ## Networking and auth