feat: implement base architecture and core repositories for weapon tracking and target analysis functionality

lib/core/theme/theme_provider.dart

@@ -0,0 +1,44 @@
+import 'package:flutter/material.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+class ThemeProvider with ChangeNotifier {
+  static const String _themeModeKey = 'user_theme_mode';
+  
+  ThemeMode _themeMode = ThemeMode.system;
+
+  ThemeMode get themeMode => _themeMode;
+
+  ThemeProvider() {
+    loadThemeMode();
+  }
+
+  Future<void> loadThemeMode() async {
+    final prefs = await SharedPreferences.getInstance();
+    final modeIndex = prefs.getInt(_themeModeKey);
+    if (modeIndex != null) {
+      _themeMode = ThemeMode.values[modeIndex];
+      notifyListeners();
+    }
+  }
+
+  Future<void> setThemeMode(ThemeMode mode) async {
+    if (_themeMode == mode) return;
+    
+    _themeMode = mode;
+    notifyListeners();
+    
+    final prefs = await SharedPreferences.getInstance();
+    await prefs.setInt(_themeModeKey, mode.index);
+  }
+
+  String get themeModeName {
+    switch (_themeMode) {
+      case ThemeMode.system:
+        return 'Automatique';
+      case ThemeMode.light:
+        return 'Clair';
+      case ThemeMode.dark:
+        return 'Sombre';
+    }
+  }
+}