feat: foreground service, dB gain sliders, speaker routing, live network stats

- Wire CallService foreground service for background calls (microphone type)
- Add Voice Volume + Mic Gain sliders (-20 to +20 dB) applied in Kotlin
- Connect AudioRouteManager for real speaker toggle via AudioManager
- Feed quinn QUIC RTT into PathMonitor, display Loss/RTT/Jitter from live data
- Nuclear teardown between calls — recreate engine + audio pipeline each call
- Fix re-entrant teardown loop from CallService notification callback
- Park audio threads as daemons to avoid libcrypto TLS destructor crash on exit
- Remove duplicate wakelocks from Activity (service owns them now)
- Strip AEC + denoise from capture path, keep AGC only (incremental approach)
- Fix .so copy target: libwzp_android.so not libwzp.so

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

android/app/src/main/java/com/wzp/service/CallService.kt

@@ -41,6 +41,7 @@ class CallService : Service() {
     override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
         when (intent?.action) {
             ACTION_STOP -> {
+                onStopFromNotification?.invoke()
                 stopSelf()
                 return START_NOT_STICKY
             }
@@ -151,6 +152,9 @@ class CallService : Service() {
         private const val ACTION_STOP = "com.wzp.service.STOP"
         private const val MAX_CALL_DURATION_MS = 4L * 60 * 60 * 1000 // 4 hours
 
+        /** Called when the user taps "End Call" in the notification. */
+        var onStopFromNotification: (() -> Unit)? = null
+
         /** Start the foreground call service. */
         fun start(context: Context) {
             val intent = Intent(context, CallService::class.java)