Android calls: single-source ring (fix double-ring), drop battery dialog, add wake logging

On-device (OnePlus, build 5cb3d0c): new ring UI confirmed; backgrounded rang
twice (channel sound + activity ringtone, and both wake paths raised it);
battery dialog deemed unprofessional (WhatsApp/Teams don't prompt it).

- Double-ring: notification channel is now SILENT (new id bzc_incoming_calls_v2,
  no sound/vibration, onlyAlertOnce) so IncomingCallActivity is the single ring
  source (looping ringtone + vibrator). showIncoming dedups atomically
  (if(!active.add(uuid)) return) so the FCM push and WebSocket paths can't both
  ring the same call.
- Battery dialog removed: dropped requestCallReliability (web call + plugin
  method) and REQUEST_IGNORE_BATTERY_OPTIMIZATIONS permission.
- Logging: Log.i(bzcall, ...) across the wake chain to diagnose swiped-away
  (OnePlus force-kills on swipe and blocks FCM cold-start).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

mobile/plugins/native-call/android/src/main/AndroidManifest.xml

@@ -6,9 +6,6 @@
     <uses-permission android:name="android.permission.USE_FULL_SCREEN_INTENT" />
     <uses-permission android:name="android.permission.VIBRATE" />
     <uses-permission android:name="android.permission.WAKE_LOCK" />
-    <!-- Ask to be exempt from battery optimization so high-priority FCM call-wakes reach the app when it's
-         been swiped away / Dozing (OnePlus/Oppo hold data messages otherwise → the ring arrives too late). -->
-    <uses-permission android:name="android.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS" />
 
     <application>
         <!-- Our FirebaseMessagingService REPLACES the @capacitor/push-notifications one: it handles call-wake