fix: 优化删除账号code传4，修改常见问题文案，禁用输入框悬浮按钮，修复登录ios输入框聚焦问题

lib/app/modules/kr_delete_account/controllers/kr_delete_account_controller.dart

@@ -58,7 +58,7 @@ class KRDeleteAccountController extends GetxController {
     // 发送验证码（简化后的 API 只需要 email 和 type）
     final result = await _authApi.kr_sendCode(
       account,  // 邮箱地址
-      2,  // 删除账号的验证码类型
+      4,  // 删除账号的验证码类型
     );
 
     result.fold(

lib/app/modules/kr_delete_account/views/kr_delete_account_view.dart

@@ -159,6 +159,7 @@ class KRDeleteAccountView extends GetView<KRDeleteAccountController> {
       height: 50.w,
       child: TextField(
         controller: controller.kr_codeController,
+        contextMenuBuilder: (context, editableTextState) => const SizedBox.shrink(),
         keyboardType: TextInputType.number,
         textInputAction: TextInputAction.done,
         autofillHints: const [AutofillHints.oneTimeCode],