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/screens/login_screen.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 import 'package:provider/provider.dart';
 import '../providers/auth_provider.dart';
 import 'package:flutter_secure_storage/flutter_secure_storage.dart';
@@ -39,6 +40,7 @@ class _LoginScreenState extends State<LoginScreen> {
       serverUrl = 'https://$serverUrl';
     }
 
+    TextInput.finishAutofillContext();
     context.read<AuthProvider>().login(
           serverUrl,
           _usernameController.text.trim(),
@@ -55,7 +57,8 @@ class _LoginScreenState extends State<LoginScreen> {
         child: Center(
           child: SingleChildScrollView(
             padding: const EdgeInsets.all(24),
-            child: Form(
+            child: AutofillGroup(
+              child: Form(
               key: _formKey,
               child: Column(
                 mainAxisSize: MainAxisSize.min,
@@ -80,6 +83,7 @@ class _LoginScreenState extends State<LoginScreen> {
                       border: OutlineInputBorder(),
                     ),
                     keyboardType: TextInputType.url,
+                    autofillHints: const [AutofillHints.url],
                     validator: (v) =>
                         v == null || v.trim().isEmpty ? 'Required' : null,
                   ),
@@ -91,6 +95,7 @@ class _LoginScreenState extends State<LoginScreen> {
                       prefixIcon: Icon(Icons.person),
                       border: OutlineInputBorder(),
                     ),
+                    autofillHints: const [AutofillHints.username],
                     validator: (v) =>
                         v == null || v.trim().isEmpty ? 'Required' : null,
                   ),
@@ -110,6 +115,7 @@ class _LoginScreenState extends State<LoginScreen> {
                       ),
                     ),
                     obscureText: _obscurePassword,
+                    autofillHints: const [AutofillHints.password],
                     validator: (v) =>
                         v == null || v.isEmpty ? 'Required' : null,
                   ),
@@ -142,6 +148,7 @@ class _LoginScreenState extends State<LoginScreen> {
                 ],
               ),
             ),
+            ),
           ),
         ),
       ),