feat: Add splash screen and update routing to include it

lib/services/auth_service.dart

@@ -69,10 +69,25 @@ class AuthService extends ChangeNotifier {
   }
 
   Future<dynamic> _httpGet(String path) async {
-    if (token == null) return null;
-    final res = await http.get(Uri.parse('$_base$path'), headers: {'Authorization': 'Bearer $token'});
-    if (res.statusCode == 200) return jsonDecode(res.body);
-    return null;
+    if (token == null) {
+      if (kDebugMode) print('[AuthService] _httpGet called without token for $path');
+      return null;
+    }
+    try {
+      final res = await http.get(Uri.parse('$_base$path'), headers: {'Authorization': 'Bearer $token'});
+      if (res.statusCode == 200) {
+        return jsonDecode(res.body);
+      } else {
+        if (kDebugMode) {
+          print('[AuthService] GET $path -> ${res.statusCode}');
+          print('[AuthService] response body: ${res.body}');
+        }
+        throw Exception('HTTP ${res.statusCode}');
+      }
+    } catch (e) {
+      if (kDebugMode) print('[AuthService] _httpGet error: $e');
+      rethrow;
+    }
   }
 
   Future<void> _loadToken() async {