feat: home hero+genres, fix Android queue desync via song ID verification

Home view:
- Add hero card (random pick from recent+frequent combined pool)
- Add genre browser chips (sorted by song count, tap = shuffle-play)

Android sync fix:
- Add currentId to getState() snapshot so JS can verify song identity
- onReady: reset stale localStorage queue when native song ID mismatches
- onTrackChanged: reject stale old-queue callbacks by ID verification
- onPlaybackStateChanged safety net: ID-guard prevents wrong-queue index corruption
- connectToService: call updateStateSnapshot() before onReady so getState() is never empty

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

android/app/src/main/kotlin/com/novasonic/app/MainActivity.kt

@@ -138,6 +138,7 @@ class MainActivity : AppCompatActivity(), MusicService.StateListener {
             mediaController = try { future.get() } catch (_: Exception) { null }
             if (mediaController != null) {
                 lastOnReadyMs = System.currentTimeMillis()
+                updateStateSnapshot()   // ensure getState() is fresh when JS calls it in onReady
                 callJs("onReady")
             }
         }, ContextCompat.getMainExecutor(this))
@@ -246,6 +247,7 @@ class MainActivity : AppCompatActivity(), MusicService.StateListener {
             put("isPlaying",    ctrl.isPlaying)
             put("isBuffering",  ctrl.playbackState == Player.STATE_BUFFERING)
             put("currentIndex", ctrl.currentMediaItemIndex)
+            put("currentId",    ctrl.currentMediaItem?.mediaId ?: "")
             put("positionMs",   ctrl.currentPosition)
             put("queueLength",  ctrl.mediaItemCount)
         }.toString()