Android M2: live rolling transcript and automatic final pass

- RecorderService: rolling-window live pass with a dedicated live model
  (off/tiny/base, beam 1, 8 s ticks, time-based dedupe) and an automatic
  final pass with the selected model (beam 5) writing txt/srt/json
- TranscriptFiles in core/whisper: desktop-compatible outputs, 5 JVM tests
- WhisperEngine exposes modelName; UI: live-model dropdown, merged
  transcript view, share sheet; falls back to manual path without engine
- live loop failures now logged (MeetRec tag) and surfaced in the UI
  (was silently swallowed), plus final-pass timing logs

On-device measurements (Fairphone 6): tiny live ~0.6x realtime, small
final ~0.8x realtime — motivates the planned whisper-server engine.

android/core/whisper/build.gradle.kts

@@ -27,4 +27,9 @@ android {
     }
 
     ndkVersion = "27.1.12297006"
+}
+
+dependencies {
+    // TranscriptFiles is pure Kotlin and unit tested on the JVM.
+    testImplementation(libs.junit)
 }