Android native calling — Increment 1: full-screen incoming ring + answer

First slice of Android Phase C (full LiveKit parity), mirroring how iOS
started: native full-screen incoming call UI that wakes the app from
closed, with call MEDIA still in the WebView (foreground). Native LiveKit
media + a foreground service for true background audio are Increment 2.

Native (new Android side of the native-call plugin, Java to match the
proven official-plugin module layout):
- NativeCallPlugin: registered as window.Capacitor.Plugins.NativeCall
  (same jsName as iOS, so the shared web bridge drives both). getToken
  (FCM token), reportIncomingCall (ring), reportOutgoingCall, endCall,
  setMuted; video/screen/hole-punch/transcript methods are safe no-ops
  until later increments so the shared bridge never rejects.
- BzCallMessagingService: extends @capacitor/push-notifications'
  MessagingService — handles high-priority call-wake DATA messages
  (data.bzcall==1) to ring when closed, forwards all other push via super.
- IncomingCallActivity: full-screen call screen over the lock screen
  (showWhenLocked/turnScreenOn), Accept/Decline, looping ringtone.
- CallStore: incoming-call notification (channel, full-screen-intent,
  actions) + UUID dedup so the FCM and WebSocket paths don't double-ring.
- Plugin manifest: BzCallMessagingService + IncomingCallActivity + call
  perms (USE_FULL_SCREEN_INTENT/VIBRATE/WAKE_LOCK).
- android-patch.js: removes Capacitor's MessagingService in the APP
  manifest (highest merge priority) so ours is the sole MESSAGING_EVENT
  receiver; ensures the tools namespace. Idempotent.
- package.json: capacitor.android.src wired.

Server (dormant until ANDROID_CALLS=1):
- push.js sendFcmData: high-priority data-only FCM (rings when closed).
  sendCallNotification rings 'android' tokens via it; sendCallCancel too.
- config.js ANDROID_CALLS flag; /api/meetings/config exposes androidCall.

Web (home.html) — platform-aware, iOS/web behavior byte-for-byte unchanged:
- setupNativeCall: Android gated on cfg.androidCall, sets _callWebViewMedia
  (native ring, WebView media); iOS keeps CallKit native-media path.
- answerCall + both outgoing sites branch on _callWebViewMedia so Android
  joins the meeting normally while the callee still rings via the server.

Safe to deploy now: dormant until ANDROID_CALLS=1 AND an APK carrying the
plugin is installed.

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

mobile/plugins/native-call/package.json

@@ -10,12 +10,17 @@
   "files": [
     "dist/",
     "ios/",
+    "android/src/main/",
+    "android/build.gradle",
     "NativeCall.podspec",
     "Package.swift"
   ],
   "capacitor": {
     "ios": {
       "src": "ios"
+    },
+    "android": {
+      "src": "android"
     }
   },
   "devDependencies": {