feat: Add fragmented MP4 (fMP4) support for Android

Implements HLS-compatible fragmented MP4 recording on Android using
AndroidX Media3 FragmentedMp4Muxer, matching the iOS implementation.

Changes:
- Add FragmentedRecordingManager for fMP4 segment output
- Add ChunkedRecorderInterface to abstract recorder implementations
- Add onInitSegmentReady callback for init segment (init.mp4)
- Update onVideoChunkReady to include segment duration
- RecordingSession now uses FragmentedRecordingManager by default

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package/android/build.gradle

@@ -178,6 +178,10 @@ dependencies {
   implementation "com.facebook.react:react-android:+"
   implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:1.7.3"
 
+  // Media3 muxer for fragmented MP4 (HLS-compatible) recording
+  implementation "androidx.media3:media3-muxer:1.5.0"
+  implementation "androidx.media3:media3-common:1.5.0"
+
   if (enableCodeScanner) {
     // User enabled code-scanner, so we bundle the 2.4 MB model in the app.
     implementation 'com.google.mlkit:barcode-scanning:17.2.0'