Fix all dart analyze warnings in the Flutter frontend

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

frontend/lib/notifications/notification_list.dart

@@ -9,7 +9,7 @@ class NotificationList extends StatefulWidget {
   const NotificationList({super.key});
 
   @override
-  _NotificationListState createState() => _NotificationListState();
+  State<NotificationList> createState() => _NotificationListState();
 }
 
 class _NotificationListState extends State<NotificationList> {
@@ -61,6 +61,7 @@ class _NotificationListState extends State<NotificationList> {
       return false;
     }
     await BackendAPI.instance.markNotificationAsRead(item.id);
+    if (!context.mounted) return false;
     ScaffoldMessenger.of(context).showSnackBar(
       SnackBar(
         content: Text('Event marked as read'),
@@ -95,6 +96,7 @@ class _NotificationListState extends State<NotificationList> {
       return false;
     }
     await BackendAPI.instance.markNotificationAsNew(item.id);
+    if (!context.mounted) return false;
     ScaffoldMessenger.of(context).showSnackBar(
       SnackBar(
         content: Text('Event marked as unread'),

frontend/lib/settings/settings.dart

@@ -12,7 +12,7 @@ class Settings extends StatefulWidget {
   const Settings({super.key});
 
   @override
-  _SettingsState createState() => _SettingsState();
+  State<Settings> createState() => _SettingsState();
 }
 
 class _SettingsState extends State<Settings> {
@@ -125,7 +125,7 @@ class _SettingsState extends State<Settings> {
                   SizedBox(height: 16),
                   // Theme selector
                   DropdownButtonFormField<String>(
-                    value: _selectedTheme,
+                    initialValue: _selectedTheme,
                     decoration: const InputDecoration(
                       border: UnderlineInputBorder(),
                       labelText: 'Theme',
@@ -162,10 +162,12 @@ class _SettingsState extends State<Settings> {
                               _apiKeyController.text,
                             );
 
+                            if (!context.mounted) return;
                             setState(() {
                               _testOk = testResult == null;
-                              if (testResult == null)
+                              if (testResult == null) {
                                 _connectionModified = false;
+                              }
                             });
 
                             if (testResult == null) {

frontend/lib/utils/friendly_date_formatter.dart

@@ -15,10 +15,12 @@ class FriendlyDateFormatter {
     );
 
     if (timeSince.inMinutes < 60) return '${timeSince.inMinutes} minutes ago';
-    if (dateTimeWithoutTime == today)
+    if (dateTimeWithoutTime == today) {
       return 'Today at ${DateFormat.Hm().format(dateTime)}';
-    if (dateTimeWithoutTime == yesterday)
+    }
+    if (dateTimeWithoutTime == yesterday) {
       return 'Yesterday at ${DateFormat.Hm().format(dateTime)}';
+    }
 
     return DateFormat.yMMMMd().add_Hm().format(dateTime);
   }

frontend/lib/utils/oott_api.dart

@@ -2,6 +2,7 @@ import 'dart:io';
 
 import 'package:dio/dio.dart';
 import 'package:encrypter/encrypter/xor.dart';
+import 'package:flutter/foundation.dart';
 import 'package:frontend/utils/pref_utils.dart';
 import '../model/notification.dart';
 
@@ -16,8 +17,8 @@ class BackendAPI {
         PrefUtil.getValue("base_url", "http://localhost:3000/api") as String;
     _apiKey = XOR().xorDecode(PrefUtil.getValue("api_key", "") as String);
 
-    print('Base URL: $_baseUrl');
-    print('API KEY $_apiKey');
+    debugPrint('Base URL: $_baseUrl');
+    debugPrint('API KEY: $_apiKey');
 
     _dio = Dio(
       BaseOptions(
@@ -32,7 +33,7 @@ class BackendAPI {
 
   // Returns null if the test was successful, and a String with a message about the issue if not
   static Future<String?> test(String baseUrl, String apiKey) async {
-    print('About to test API with baseUrl=$baseUrl and apiKey=$apiKey');
+    debugPrint('About to test API with baseUrl=$baseUrl and apiKey=$apiKey');
     Dio dio = Dio(
       BaseOptions(
         baseUrl: baseUrl,
@@ -67,22 +68,22 @@ class BackendAPI {
   late Dio _dio;
 
   Future<void> markNotificationAsRead(int id) async {
-    print('About to call /notifications/$id');
+    debugPrint('About to call /notifications/$id');
     await _dio.get('/notifications/$id');
   }
 
   Future<void> markNotificationAsNew(int id) async {
-    print('About to call /notifications/$id/mark_as_new');
+    debugPrint('About to call /notifications/$id/mark_as_new');
     await _dio.post('/notifications/$id/mark_as_new');
   }
 
   Future<void> markAllNotificationsAsRead() async {
-    print('About to call /notifications/mark_all_as_old');
+    debugPrint('About to call /notifications/mark_all_as_old');
     await _dio.post('/notifications/mark_all_as_old');
   }
 
   Future<List<Notification>> listNotifications(bool? isNew, int offset) async {
-    print('About to call /notifications');
+    debugPrint('About to call /notifications');
 
     Response response;
     response = await _dio.get(
@@ -94,16 +95,16 @@ class BackendAPI {
       },
     );
 
-    print('Received: ' + response.data.toString());
+    debugPrint('Received: ${response.data}');
 
     List<dynamic> list = response.data;
-    print('List contains ' + list.length.toString() + ' items');
+    debugPrint('List contains ${list.length} items');
 
     List<Notification> events = List<Notification>.from(
       list.map((item) => Notification.fromJson(item)),
     );
 
-    print('Parsed ' + events.length.toString() + ' events');
+    debugPrint('Parsed ${events.length} events');
 
     return events;
   }

frontend/lib/utils/pref_utils.dart

@@ -11,27 +11,24 @@ class PrefUtil {
   }
 
   static void setValue(String key, Object value) {
-    switch (value.runtimeType) {
-      case String:
-        preferences.setString(key, value as String);
-        break;
-      case bool:
-        preferences.setBool(key, value as bool);
-        break;
-      case int:
-        preferences.setInt(key, value as int);
-        break;
+    switch (value) {
+      case String s:
+        preferences.setString(key, s);
+      case bool b:
+        preferences.setBool(key, b);
+      case int i:
+        preferences.setInt(key, i);
       default:
     }
   }
 
   static Object getValue(String key, Object defaultValue) {
-    switch (defaultValue.runtimeType) {
-      case String:
+    switch (defaultValue) {
+      case String _:
         return preferences.getString(key) ?? defaultValue;
-      case bool:
+      case bool _:
         return preferences.getBool(key) ?? defaultValue;
-      case int:
+      case int _:
         return preferences.getInt(key) ?? defaultValue;
       default:
         return defaultValue;