Add auth session flow and sign-in UX

lib/features/settings/settings_view.dart

@@ -1,13 +1,21 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:relationship_saver/core/config/app_config.dart';
 import 'package:relationship_saver/core/config/app_theme.dart';
+import 'package:relationship_saver/features/auth/session_controller.dart';
 import 'package:relationship_saver/features/shared/frosted_card.dart';
+import 'package:relationship_saver/integrations/backend/models/backend_models.dart';
 
-class SettingsView extends StatelessWidget {
+class SettingsView extends ConsumerWidget {
   const SettingsView({super.key});
 
   @override
-  Widget build(BuildContext context) {
+  Widget build(BuildContext context, WidgetRef ref) {
+    final AuthSession? session = ref
+        .watch(sessionControllerProvider)
+        .asData
+        ?.value;
+
     return Padding(
       padding: const EdgeInsets.fromLTRB(28, 24, 28, 28),
       child: Column(
@@ -26,6 +34,14 @@ class SettingsView extends StatelessWidget {
             child: Column(
               crossAxisAlignment: CrossAxisAlignment.start,
               children: <Widget>[
+                _SettingRow(
+                  label: 'Signed in as',
+                  value:
+                      session?.user.email ??
+                      session?.user.id ??
+                      'Not signed in',
+                ),
+                const SizedBox(height: 12),
                 _SettingRow(
                   label: 'Gateway mode',
                   value: AppConfig.useFakeBackend
@@ -39,6 +55,30 @@ class SettingsView extends StatelessWidget {
                   label: 'Realtime',
                   value: 'Planned later (SSE/WebSocket)',
                 ),
+                const SizedBox(height: 14),
+                Row(
+                  children: <Widget>[
+                    FilledButton.icon(
+                      onPressed: session == null
+                          ? null
+                          : () => _signOut(context, ref),
+                      icon: const Icon(Icons.logout_rounded),
+                      label: const Text('Sign Out'),
+                    ),
+                    const SizedBox(width: 8),
+                    OutlinedButton.icon(
+                      onPressed: session == null
+                          ? null
+                          : () {
+                              ref
+                                  .read(sessionControllerProvider.notifier)
+                                  .refreshProfile();
+                            },
+                      icon: const Icon(Icons.refresh_rounded),
+                      label: const Text('Refresh Profile'),
+                    ),
+                  ],
+                ),
               ],
             ),
           ),
@@ -53,6 +93,15 @@ class SettingsView extends StatelessWidget {
       ),
     );
   }
+
+  Future<void> _signOut(BuildContext context, WidgetRef ref) async {
+    await ref.read(sessionControllerProvider.notifier).signOut();
+    if (context.mounted) {
+      ScaffoldMessenger.of(
+        context,
+      ).showSnackBar(const SnackBar(content: Text('Signed out.')));
+    }
+  }
 }
 
 class _SettingRow extends StatelessWidget {