fix(auth): add navigation debounce for register next button

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

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:formz/formz.dart';
@@ -49,7 +51,7 @@ class _RegisterViewState extends State<RegisterView> {
     cubit.emailChanged(_emailController.text);
     cubit.passwordChanged(_passwordController.text);
 
-    if (!cubit.state.isStep1Valid) {
+    if (!cubit.state.isStep1Valid || cubit.state.isSending) {
       return;
     }
 
@@ -57,7 +59,7 @@ class _RegisterViewState extends State<RegisterView> {
       context.push('/register/verification', extra: cubit);
     }
 
-    cubit.sendCodeSilently();
+    unawaited(cubit.sendCodeSilently());
   }
 
   @override
@@ -157,7 +159,9 @@ class _RegisterViewState extends State<RegisterView> {
               const SizedBox(height: 12),
               AppButton(
                 text: '下一步',
-                onPressed: state.status == FormzSubmissionStatus.inProgress
+                onPressed:
+                    state.status == FormzSubmissionStatus.inProgress ||
+                        state.isSending
                     ? null
                     : _handleNext,
               ),