logging: add release-visible breadcrumbs and a verbose toggle

Playback now logs each track transition and end at info (title/artist/album/source/reason), sync logs per-entity counts and pruned rows, and the Subsonic client logs server error codes and the token-auth fallback. Add a Verbose logging setting that drops the file level to debug at runtime (persisted) so a support session can capture full detail without flooding normal release logs.

app/src/main/kotlin/com/subtracks/ui/settings/SettingsViewModel.kt

@@ -55,10 +55,19 @@ class SettingsViewModel(
 
     val offline: StateFlow<Boolean> = sourceRepository.offline
 
+    val verboseLogging: StateFlow<Boolean> =
+        userPreferences
+            .verboseLogging()
+            .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), false)
+
     fun setOfflineMode(enabled: Boolean) {
         sourceRepository.setOfflineMode(enabled)
     }
 
+    fun setVerboseLogging(enabled: Boolean) {
+        viewModelScope.launch { userPreferences.setVerboseLogging(enabled) }
+    }
+
     fun selectSource(id: Long) {
         viewModelScope.launch { sourceRepository.selectSource(id) }
     }