fix(auth): improve resendCode with status tracking and return value

apps/lib/features/auth/presentation/cubits/register_cubit.dart

@@ -152,17 +152,28 @@ class RegisterCubit extends Cubit<RegisterState> {
     }
   }
 
-  Future<void> resendCode() async {
-    if (state.pendingEmail == null) return;
+  Future<bool> resendCode() async {
+    if (state.pendingEmail == null) return false;
+
+    emit(state.copyWith(status: FormzSubmissionStatus.inProgress));
 
     try {
       await _repository.signupResend(
         SignupResendRequest(email: state.pendingEmail!),
       );
-      emit(state.copyWith(codeSent: true));
+      emit(
+        state.copyWith(status: FormzSubmissionStatus.success, codeSent: true),
+      );
+      return true;
     } catch (e) {
-      final message = e is ApiException ? e.message : e.toString();
-      emit(state.copyWith(errorMessage: message));
+      final message = e is ApiException ? e.message : '验证码发送失败，请重试';
+      emit(
+        state.copyWith(
+          status: FormzSubmissionStatus.failure,
+          errorMessage: message,
+        ),
+      );
+      return false;
     }
   }
 

apps/lib/features/auth/ui/screens/register_verification_screen.dart

@@ -94,9 +94,9 @@ class _RegisterVerificationViewState extends State<RegisterVerificationView> {
 
   Future<void> _handleResendCode() async {
     final cubit = context.read<RegisterCubit>();
-    await cubit.resendCode();
+    final success = await cubit.resendCode();
 
-    if (cubit.state.codeSent && mounted) {
+    if (success && mounted) {
       _startCountdown();
     }
   }