Add FCM push notifications, queue alerts, caller ID fixes, and auto-revert agent status

Server-side:
- Add push credential auto-creation for FCM incoming call notifications
- Add queue alert FCM notifications (data-only for background delivery)
- Add queue alert cancellation on call accept/disconnect
- Fix caller ID to show caller's number instead of Twilio number
- Fix FCM token storage when refresh_token is null
- Add pre_call_status tracking to revert agent status 30s after call ends
- Add SSE fallback polling for mobile app connectivity

Mobile app:
- Add Android telecom permissions and phone account registration
- Add VoiceFirebaseMessagingService for incoming call push handling
- Add insistent queue alert notifications with custom sound
- Fix caller number display on active call screen
- Add caller ID selection dropdown on dashboard
- Add phone numbers endpoint and provider support
- Add unit tests for CallInfo, QueueState, and CallProvider
- Remove local.properties from tracking, add .gitignore

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

mobile/lib/widgets/queue_card.dart

@@ -3,13 +3,15 @@ import '../models/queue_state.dart';
 
 class QueueCard extends StatelessWidget {
   final QueueInfo queue;
+  final VoidCallback? onTap;
 
-  const QueueCard({super.key, required this.queue});
+  const QueueCard({super.key, required this.queue, this.onTap});
 
   @override
   Widget build(BuildContext context) {
     return Card(
       child: ListTile(
+        onTap: onTap,
         leading: CircleAvatar(
           backgroundColor: queue.waitingCount > 0
               ? Colors.orange.shade100