Android: fix upload lifecycle and JNI UTF-8 abort (M3a hardening)

- upload ran as a detached coroutine while cleanup() stopped the
  service, and onDestroy's scope.cancel() killed it before any status
  appeared; the upload is now part of finishRecording itself and the
  service stays foreground ("Saving recording…") until it completes
- JNI getTextSegment used NewStringUTF, which ABORTS THE PROCESS on
  invalid UTF-8 — whisper can emit garbled bytes on noisy audio (seen
  live: SIGABRT with illegal start byte 0x8d); whisper_jni.cpp now
  decodes UTF-8 to UTF-16 itself, replacing bad sequences with U+FFFD
- validated on device end-to-end: record -> local final pass -> automatic
  upload -> library entry with all four files (verified server-side)

android/app/src/main/java/com/meetrec/android/RecorderService.kt

@@ -266,7 +266,12 @@ class RecorderService : Service() {
         }
     }
 
-    /** Final pass + outputs, after the WAV is safely closed. */
+    /**
+     * Final pass + upload + outputs, after the WAV is safely closed.
+     * The service stays foreground ("Saving recording…") until the
+     * upload is done — stopping earlier would cancel the upload
+     * coroutine via onDestroy's scope.cancel().
+     */
     private suspend fun finishRecording(file: File, durationMs: Long, sampleRate: Int) {
         // let the live loop drain its current window first
         liveJob?.cancel()
@@ -276,54 +281,43 @@ class RecorderService : Service() {
         val cfg = session
         val transcriber: Transcriber? =
             cfg?.serverUrl?.let { RemoteWhisperEngine(it) } ?: cfg?.finalEngine
+
+        var outputs: List<File> = emptyList()
         if (transcriber == null) {
             _state.value = RecordingState.Finished(file, durationMs, sampleRate)
-            maybeUpload(file, emptyList(), durationMs, cfg)
-            cleanup()
-            return
-        }
-
-        _state.value = RecordingState.Finalizing(file, durationMs)
-        updateNotification("Transcribing meeting…")
-        try {
-            val t0 = SystemClock.elapsedRealtime()
-            val samples = withContext(Dispatchers.IO) {
-                file.inputStream().use { WavReader.read(it) }
+        } else {
+            _state.value = RecordingState.Finalizing(file, durationMs)
+            updateNotification("Transcribing meeting…")
+            try {
+                val t0 = SystemClock.elapsedRealtime()
+                val samples = withContext(Dispatchers.IO) {
+                    file.inputStream().use { WavReader.read(it) }
+                }
+                val segments = transcriber.transcribe(
+                    samples,
+                    WhisperEngine.DEFAULT_THREADS,
+                    beamSize = 5,
+                    language = cfg?.language,
+                )
+                Log.i(TAG, "final: ${segments.size} segments in " +
+                    "${SystemClock.elapsedRealtime() - t0} ms")
+                outputs = TranscriptFiles.writeAll(file, durationMs, segments)
+                _state.value = RecordingState.Finished(file, durationMs, sampleRate, segments, outputs)
+            } catch (e: Exception) {
+                _state.value = RecordingState.Finished(
+                    file, durationMs, sampleRate, error = e.message,
+                )
             }
-            val segments = transcriber.transcribe(
-                samples,
-                WhisperEngine.DEFAULT_THREADS,
-                beamSize = 5,
-                language = cfg?.language,
-            )
-            Log.i(TAG, "final: ${segments.size} segments in " +
-                "${SystemClock.elapsedRealtime() - t0} ms")
-            val outputs = TranscriptFiles.writeAll(file, durationMs, segments)
-            _state.value = RecordingState.Finished(file, durationMs, sampleRate, segments, outputs)
-            maybeUpload(file, outputs, durationMs, cfg)
-        } catch (e: Exception) {
-            _state.value = RecordingState.Finished(
-                file, durationMs, sampleRate, error = e.message,
-            )
         }
-        cleanup()
-    }
 
-    /** Uploads the bundle to the recording library in the background. */
-    private fun maybeUpload(
-        file: File,
-        outputs: List<File>,
-        durationMs: Long,
-        cfg: SessionConfig?,
-    ) {
-        val url = cfg?.storageUrl?.trim()
-        if (url.isNullOrBlank()) return
-        scope.launch {
+        val storageUrl = cfg?.storageUrl?.trim()
+        if (!storageUrl.isNullOrBlank()) {
+            updateNotification("Saving recording…")
             _uploadState.value = UploadState.Uploading(file)
             try {
                 val id = withContext(Dispatchers.IO) {
                     StorageClient.upload(
-                        baseUrl = url,
+                        baseUrl = storageUrl,
                         wav = file,
                         txt = outputs.firstOrNull { it.name.endsWith(".txt") },
                         srt = outputs.firstOrNull { it.name.endsWith(".srt") },
@@ -342,6 +336,7 @@ class RecorderService : Service() {
                 _uploadState.value = UploadState.Error(e.message ?: "upload failed")
             }
         }
+        cleanup()
     }
 
     private fun cleanup() {