Phase 5: Offline downloads at selectable bitrates

Adds Room + WorkManager-backed offline downloads: a bitrate picker
(Low/Normal/High/Original) on track and album detail screens, a
Downloads library screen, and Settings additions for Wi-Fi-only
downloads and default quality. Bitrate tiers route through Subsonic's
`stream` endpoint with `maxBitRate`; Original uses `download`, which
always returns the untranscoded source file.

Three real bugs found and fixed during on-device verification:

- WorkManager was constructing DownloadWorker with its default
  reflection-based WorkerFactory instead of HiltWorkerFactory
  (NoSuchMethodException on the @AssistedInject constructor). The
  default androidx.startup auto-init ran before Hilt's field
  injection was guaranteed to have happened. Fixed by disabling the
  manifest's auto-init provider and calling WorkManager.initialize()
  manually in DeepwaveApplication.onCreate(), after super.onCreate().

- Crash on every download: WorkManager's own SystemForegroundService
  declares no foregroundServiceType in its manifest, but the worker
  requests dataSync at runtime via ForegroundInfo, which API 29+
  requires to be a subset of what's manifest-declared. Fixed by
  manifest-merging that service with foregroundServiceType="dataSync".

- Offline playback was completely broken: ResolvingDataSource only
  rewrites the DataSpec's URI (to file:// for a downloaded track) but
  always hands it to the same wrapped upstream DataSource to open.
  OkHttpDataSource can only open http(s) URLs, so the rewritten
  file:// URI failed with "Malformed URL" and playback silently fell
  through to the network. Wrapping the signed OkHttpDataSource.Factory
  in DefaultDataSource.Factory routes by scheme instead - this bug was
  latent since Phase 4, since LocalTrackFiles was always empty until
  now and the local-file path was never actually exercised.

- Re-downloading a track at a different quality could produce a
  different file extension (Content-Type-driven), orphaning the
  previous file on disk with no cleanup path. DownloadWorker now
  clears any existing files for the track id before writing the new
  one.

Verified on-device: downloads at all four tiers produce distinctly
different, correctly-ordered file sizes (Low < Normal < High <
Original); a fully downloaded track keeps playing with Wi-Fi and
mobile data both disabled; killing and relaunching the app mid-download
lets WorkManager resume the interrupted download to a correct,
byte-exact final file.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

gradle/libs.versions.toml

@@ -22,6 +22,8 @@ coil = "3.3.0"
 media3 = "1.11.1"
 mockitoCore = "5.23.0"
 kotlinxCoroutinesTest = "1.11.0"
+room = "2.8.5"
+workManager = "2.11.2"
 
 [libraries]
 androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
@@ -44,6 +46,8 @@ androidx-lifecycle-viewmodel-compose = { group = "androidx.lifecycle", name = "l
 hilt-android = { group = "com.google.dagger", name = "hilt-android", version.ref = "hiltAndroid" }
 hilt-compiler = { group = "com.google.dagger", name = "hilt-compiler", version.ref = "hiltAndroid" }
 androidx-hilt-lifecycle-viewmodel-compose = { group = "androidx.hilt", name = "hilt-lifecycle-viewmodel-compose", version.ref = "androidxHilt" }
+androidx-hilt-work = { group = "androidx.hilt", name = "hilt-work", version.ref = "androidxHilt" }
+androidx-hilt-compiler = { group = "androidx.hilt", name = "hilt-compiler", version.ref = "androidxHilt" }
 retrofit = { group = "com.squareup.retrofit2", name = "retrofit", version.ref = "retrofit" }
 retrofit-kotlinx-serialization-converter = { group = "com.jakewharton.retrofit", name = "retrofit2-kotlinx-serialization-converter", version.ref = "retrofitKotlinxSerializationConverter" }
 okhttp = { group = "com.squareup.okhttp3", name = "okhttp", version.ref = "okhttp" }
@@ -59,6 +63,12 @@ androidx-media3-datasource-okhttp = { group = "androidx.media3", name = "media3-
 okhttp-mockwebserver = { group = "com.squareup.okhttp3", name = "mockwebserver3", version.ref = "okhttp" }
 mockito-core = { group = "org.mockito", name = "mockito-core", version.ref = "mockitoCore" }
 kotlinx-coroutines-test = { group = "org.jetbrains.kotlinx", name = "kotlinx-coroutines-test", version.ref = "kotlinxCoroutinesTest" }
+androidx-room-runtime = { group = "androidx.room", name = "room-runtime", version.ref = "room" }
+androidx-room-ktx = { group = "androidx.room", name = "room-ktx", version.ref = "room" }
+androidx-room-compiler = { group = "androidx.room", name = "room-compiler", version.ref = "room" }
+androidx-room-testing = { group = "androidx.room", name = "room-testing", version.ref = "room" }
+androidx-work-runtime-ktx = { group = "androidx.work", name = "work-runtime-ktx", version.ref = "workManager" }
+androidx-work-testing = { group = "androidx.work", name = "work-testing", version.ref = "workManager" }
 
 [plugins]
 android-application = { id = "com.android.application", version.ref = "agp" }