refactor(frontend): adapt to RESTful API routes

apps/lib/features/auth/data/models/auth_response.dart

@@ -35,32 +35,12 @@ class AuthResponse {
   }
 }
 
-class SignupStartResponse {
-  final String status;
+class VerificationCreateResponse {
   final String email;
-  final String message;
 
-  const SignupStartResponse({
-    required this.status,
-    required this.email,
-    required this.message,
-  });
+  const VerificationCreateResponse({required this.email});
 
-  factory SignupStartResponse.fromJson(Map<String, dynamic> json) {
-    return SignupStartResponse(
-      status: json['status'] as String,
-      email: json['email'] as String,
-      message: json['message'] as String,
-    );
-  }
-}
-
-class SignupResendResponse {
-  final String message;
-
-  const SignupResendResponse({required this.message});
-
-  factory SignupResendResponse.fromJson(Map<String, dynamic> json) {
-    return SignupResendResponse(message: json['message'] as String);
+  factory VerificationCreateResponse.fromJson(Map<String, dynamic> json) {
+    return VerificationCreateResponse(email: json['email'] as String);
   }
 }