feat: Add settings provider for theme and time range management

- Implemented SettingsProvider to manage user preferences for theme options and time ranges for reminders.
- Added persistent reminder settings with configurable retry intervals and maximum attempts.
- Created UI for settings screen to allow users to customize their preferences.
- Integrated shared_preferences for persistent storage of user settings.

feat: Introduce Ingredient model

- Created Ingredient model to represent nutritional components with properties for id, name, amount, and unit.
- Added methods for serialization and deserialization of Ingredient objects.

feat: Develop Archived Supplements Screen

- Implemented ArchivedSupplementsScreen to display archived supplements with options to unarchive or delete.
- Added UI components for listing archived supplements and handling user interactions.

chore: Update dependencies in pubspec.yaml and pubspec.lock

- Updated shared_preferences dependency to the latest version.
- Removed flutter_datetime_picker_plus dependency and added file dependency.
- Updated Flutter SDK constraint to >=3.27.0.

lib/main.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 import 'providers/supplement_provider.dart';
+import 'providers/settings_provider.dart';
 import 'screens/home_screen.dart';
 
 void main() {
@@ -12,27 +13,38 @@ class MyApp extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return ChangeNotifierProvider(
-      create: (context) => SupplementProvider()..initialize(),
-      child: MaterialApp(
-        title: 'Supplements Tracker',
-        theme: ThemeData(
-          colorScheme: ColorScheme.fromSeed(
-            seedColor: Colors.blue,
-            brightness: Brightness.light,
-          ),
-          useMaterial3: true,
+    return MultiProvider(
+      providers: [
+        ChangeNotifierProvider(
+          create: (context) => SupplementProvider()..initialize(),
         ),
-        darkTheme: ThemeData(
-          colorScheme: ColorScheme.fromSeed(
-            seedColor: Colors.blue,
-            brightness: Brightness.dark,
-          ),
-          useMaterial3: true,
+        ChangeNotifierProvider(
+          create: (context) => SettingsProvider()..initialize(),
         ),
-        themeMode: ThemeMode.system, // Follows system theme
-        home: const HomeScreen(),
-        debugShowCheckedModeBanner: false,
+      ],
+      child: Consumer<SettingsProvider>(
+        builder: (context, settingsProvider, child) {
+          return MaterialApp(
+            title: 'Supplements Tracker',
+            theme: ThemeData(
+              colorScheme: ColorScheme.fromSeed(
+                seedColor: Colors.blue,
+                brightness: Brightness.light,
+              ),
+              useMaterial3: true,
+            ),
+            darkTheme: ThemeData(
+              colorScheme: ColorScheme.fromSeed(
+                seedColor: Colors.blue,
+                brightness: Brightness.dark,
+              ),
+              useMaterial3: true,
+            ),
+            themeMode: settingsProvider.themeMode,
+            home: const HomeScreen(),
+            debugShowCheckedModeBanner: false,
+          );
+        },
       ),
     );
   }