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/providers/agent_provider.dart

@@ -1,4 +1,5 @@
 import 'dart:async';
+import 'package:dio/dio.dart';
 import 'package:flutter/foundation.dart';
 import '../models/agent_status.dart';
 import '../models/queue_state.dart';
@@ -25,6 +26,7 @@ class AgentProvider extends ChangeNotifier {
   List<PhoneNumber> _phoneNumbers = [];
   StreamSubscription? _sseSub;
   StreamSubscription? _connSub;
+  Timer? _refreshTimer;
 
   AgentStatus? get status => _status;
   List<QueueInfo> get queues => _queues;
@@ -38,6 +40,11 @@ class AgentProvider extends ChangeNotifier {
     });
 
     _sseSub = _sse.events.listen(_handleSseEvent);
+
+    _refreshTimer = Timer.periodic(
+      const Duration(seconds: 15),
+      (_) => fetchQueues(),
+    );
   }
 
   Future<void> fetchStatus() async {
@@ -45,7 +52,10 @@ class AgentProvider extends ChangeNotifier {
       final response = await _api.dio.get('/agent/status');
       _status = AgentStatus.fromJson(response.data);
       notifyListeners();
-    } catch (e) { debugPrint('AgentProvider.fetchStatus error: $e'); }
+    } catch (e) {
+      debugPrint('AgentProvider.fetchStatus error: $e');
+      if (e is DioException) debugPrint('  response: ${e.response?.data}');
+    }
   }
 
   Future<void> updateStatus(AgentStatusValue newStatus) async {
@@ -61,7 +71,12 @@ class AgentProvider extends ChangeNotifier {
         currentCallSid: _status?.currentCallSid,
       );
       notifyListeners();
-    } catch (e) { debugPrint('AgentProvider.updateStatus error: $e'); }
+    } catch (e) {
+      debugPrint('AgentProvider.updateStatus error: $e');
+      if (e is DioException) {
+        debugPrint('AgentProvider.updateStatus response: ${e.response?.data}');
+      }
+    }
   }
 
   Future<void> fetchQueues() async {
@@ -72,7 +87,10 @@ class AgentProvider extends ChangeNotifier {
           .map((q) => QueueInfo.fromJson(q as Map<String, dynamic>))
           .toList();
       notifyListeners();
-    } catch (e) { debugPrint('AgentProvider.fetchQueues error: $e'); }
+    } catch (e) {
+      debugPrint('AgentProvider.fetchQueues error: $e');
+      if (e is DioException) debugPrint('  response: ${e.response?.data}');
+    }
   }
 
   Future<void> fetchPhoneNumbers() async {
@@ -106,6 +124,7 @@ class AgentProvider extends ChangeNotifier {
 
   @override
   void dispose() {
+    _refreshTimer?.cancel();
     _sseSub?.cancel();
     _connSub?.cancel();
     super.dispose();