Change core prefs to use code generation

lib/core/prefs/theme_prefs.dart

@@ -1,14 +1,39 @@
 import 'package:flutter/material.dart';
+import 'package:hiddify/data/data_providers.dart';
 import 'package:hiddify/utils/pref_notifier.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
 
-final themeModeProvider = AlwaysAlivePrefNotifier.provider(
-  "theme_mode",
-  ThemeMode.system,
-  mapFrom: ThemeMode.values.byName,
-  mapTo: (value) => value.name,
-);
+part 'theme_prefs.g.dart';
 
-final trueBlackThemeProvider = AlwaysAlivePrefNotifier.provider(
-  "true_black_theme",
-  false,
-);
+@Riverpod(keepAlive: true)
+class ThemeModeNotifier extends _$ThemeModeNotifier {
+  late final _pref = Pref(
+    ref.watch(sharedPreferencesProvider),
+    "theme_mode",
+    ThemeMode.system,
+    mapFrom: ThemeMode.values.byName,
+    mapTo: (value) => value.name,
+  );
+
+  @override
+  ThemeMode build() => _pref.getValue();
+
+  Future<void> update(ThemeMode value) {
+    state = value;
+    return _pref.update(value);
+  }
+}
+
+@Riverpod(keepAlive: true)
+class TrueBlackThemeNotifier extends _$TrueBlackThemeNotifier {
+  late final _pref =
+      Pref(ref.watch(sharedPreferencesProvider), "true_black_theme", false);
+
+  @override
+  bool build() => _pref.getValue();
+
+  Future<void> update(bool value) {
+    state = value;
+    return _pref.update(value);
+  }
+}