Fix queue loading, null-safe models, autofill, and add outbound dialer

- Fix queue queries in mobile API and SSE to use twp_group_members
  (matching browser phone) instead of twp_queue_assignments
- Auto-create personal queues if user has no extension
- Make all model JSON parsing null-safe (handle null, string ints, bools)
- Add AutofillGroup and autofill hints to login form
- Add outbound calling with dialpad bottom sheet on dashboard

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

mobile/lib/models/user.dart

@@ -13,10 +13,16 @@ class User {
 
   factory User.fromJson(Map<String, dynamic> json) {
     return User(
-      id: json['user_id'] as int,
-      login: json['user_login'] as String,
-      displayName: json['display_name'] as String,
+      id: _toInt(json['user_id']),
+      login: (json['user_login'] ?? '') as String,
+      displayName: (json['display_name'] ?? '') as String,
       email: json['email'] as String?,
     );
   }
+
+  static int _toInt(dynamic value) {
+    if (value is int) return value;
+    if (value is String) return int.tryParse(value) ?? 0;
+    return 0;
+  }
 }