feat: Add splash screen and update routing to include it

lib/main.dart

@@ -4,6 +4,7 @@ import 'package:provider/provider.dart';
 import 'screens/login_screen.dart';
 import 'screens/profile_screen.dart';
 import 'screens/schedule_screen.dart';
+import 'screens/splash_screen.dart';
 import 'services/auth_service.dart';
 
 void main() {
@@ -21,8 +22,9 @@ class MyApp extends StatelessWidget {
           primaryColor: Color(0xFFA24BFA),
           scaffoldBackgroundColor: Color(0xFF0c0a0a),
         ),
-        initialRoute: '/',
+        initialRoute: '/splash',
         routes: {
+          '/splash': (context) => SplashScreen(),
           '/': (context) => LoginScreen(),
           '/profile': (context) => ProfileScreen(),
           '/schedule': (context) => ScheduleScreen(),