feat: deploy infrastructure + disk/drive, calendar, presentation, workspaces, onboarding, demo user

flutter/lib/providers/theme_provider.dart

@@ -0,0 +1,33 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_secure_storage/flutter_secure_storage.dart';
+
+final themeModeProvider =
+    StateNotifierProvider<ThemeModeNotifier, ThemeMode>((ref) {
+  return ThemeModeNotifier();
+});
+
+class ThemeModeNotifier extends StateNotifier<ThemeMode> {
+  ThemeModeNotifier() : super(ThemeMode.system) {
+    _load();
+  }
+
+  final _storage = const FlutterSecureStorage();
+  static const _key = 'theme_mode';
+
+  Future<void> _load() async {
+    final value = await _storage.read(key: _key);
+    if (value == 'light') state = ThemeMode.light;
+    if (value == 'dark') state = ThemeMode.dark;
+  }
+
+  Future<void> setTheme(ThemeMode mode) async {
+    state = mode;
+    final value = mode == ThemeMode.light
+        ? 'light'
+        : mode == ThemeMode.dark
+            ? 'dark'
+            : 'system';
+    await _storage.write(key: _key, value: value);
+  }
+}