feat(audio): Background-Service auch fuer Wake-Word + Aufnahme + Doku-Split

Erweitert den Foreground-Service um den microphone-Type damit nicht nur
TTS, sondern auch Wake-Word-Lauschen und aktive Aufnahmen weiterlaufen
wenn die App im Hintergrund ist.

Slot-System (backgroundAudio.ts):
- 'tts'  : ARIA spricht
- 'rec'  : Aufnahme laeuft
- 'wake' : Wake-Word lauscht passiv (Ohr aktiv)
Mehrere Slots koennen unabhaengig acquired/released werden, der Service
laeuft solange mindestens einer aktiv ist. Notification-Text passt sich
dynamisch an den hoechstprioren Slot an (tts > rec > wake).

Wiring (ChatScreen):
- onPlaybackStarted/Finished → 'tts' Slot
- audioService.onStateChange (recording) → 'rec' Slot
- wakeWordService.onStateChange (off→armed/conversing) → 'wake' Slot

AndroidManifest:
- foregroundServiceType="mediaPlayback|microphone" (Pflicht ab Android 14
  fuer Background-Mic-Zugriff)
- FOREGROUND_SERVICE_MICROPHONE Permission

Doku:
- issue.md Erledigt-Sektion in "Bugs / Fixes", "App Features" und
  "Infrastruktur" gesplittet
- README: Background-Service-Beschreibung erweitert

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

android/android/app/src/main/java/com/ariacockpit/AriaPlaybackService.kt

@@ -27,17 +27,22 @@ class AriaPlaybackService : Service() {
         private const val TAG = "AriaPlaybackService"
         private const val CHANNEL_ID = "aria_playback"
         private const val NOTIFICATION_ID = 1042
+        const val EXTRA_REASON = "reason"  // "tts" | "wake" | "rec" | ""
     }
 
+    private var currentReason: String = ""
+
     override fun onCreate() {
         super.onCreate()
         ensureNotificationChannel()
     }
 
     override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
-        Log.i(TAG, "Foreground-Service gestartet")
+        val reason = intent?.getStringExtra(EXTRA_REASON) ?: ""
+        currentReason = reason
+        Log.i(TAG, "Foreground-Service start/update (reason=$reason)")
         try {
-            startForeground(NOTIFICATION_ID, buildNotification())
+            startForeground(NOTIFICATION_ID, buildNotification(reason))
         } catch (e: Exception) {
             Log.e(TAG, "startForeground fehlgeschlagen", e)
             stopSelf()
@@ -71,7 +76,7 @@ class AriaPlaybackService : Service() {
         }
     }
 
-    private fun buildNotification(): Notification {
+    private fun buildNotification(reason: String): Notification {
         val launchIntent = Intent(this, MainActivity::class.java).apply {
             flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TOP
         }
@@ -81,9 +86,16 @@ class AriaPlaybackService : Service() {
             PendingIntent.FLAG_UPDATE_CURRENT
         val pendingIntent = PendingIntent.getActivity(this, 0, launchIntent, pendingFlags)
 
+        val (title, body) = when (reason) {
+            "tts"  -> "ARIA spricht" to "Antwort wird abgespielt — antippen oeffnet die App"
+            "rec"  -> "ARIA hoert zu" to "Sprachaufnahme laeuft — antippen oeffnet die App"
+            "wake" -> "ARIA bereit"   to "Wake-Word lauscht passiv — antippen oeffnet die App"
+            else   -> "ARIA aktiv"    to "Hintergrund-Modus — antippen oeffnet die App"
+        }
+
         return NotificationCompat.Builder(this, CHANNEL_ID)
-            .setContentTitle("ARIA spricht")
-            .setContentText("Antwort wird abgespielt — antippen oeffnet die App")
+            .setContentTitle(title)
+            .setContentText(body)
             .setSmallIcon(R.mipmap.ic_launcher)
             .setContentIntent(pendingIntent)
             .setOngoing(true)

android/android/app/src/main/java/com/ariacockpit/BackgroundAudioModule.kt

@@ -25,10 +25,11 @@ class BackgroundAudioModule(reactContext: ReactApplicationContext) : ReactContex
     companion object { private const val TAG = "BackgroundAudio" }
 
     @ReactMethod
-    fun start(promise: Promise) {
+    fun start(reason: String, promise: Promise) {
         try {
             val ctx = reactApplicationContext
             val intent = Intent(ctx, AriaPlaybackService::class.java)
+            intent.putExtra(AriaPlaybackService.EXTRA_REASON, reason ?: "")
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                 ctx.startForegroundService(intent)
             } else {