refactor: 使用 ConfirmDialog 组件替代原生 confirm() 对话框

- EditAccountModal 和 CreateAccountModal 使用 ConfirmDialog 组件
- 保存 pending payload 供确认后重试
- 添加 mixedChannelWarningTitle 翻译

Co-authored-by: factory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>

frontend/src/components/account/CreateAccountModal.vue

@@ -1615,6 +1615,18 @@
       </div>
     </template>
   </BaseDialog>
+
+  <!-- Mixed Channel Warning Dialog -->
+  <ConfirmDialog
+    :show="showMixedChannelWarning"
+    :title="t('admin.accounts.mixedChannelWarningTitle')"
+    :message="mixedChannelWarningDetails ? t('admin.accounts.mixedChannelWarning', mixedChannelWarningDetails) : ''"
+    :confirm-text="t('common.confirm')"
+    :cancel-text="t('common.cancel')"
+    :danger="true"
+    @confirm="handleMixedChannelConfirm"
+    @cancel="handleMixedChannelCancel"
+  />
 </template>
 
 <script setup lang="ts">
@@ -1634,6 +1646,7 @@ import { useGeminiOAuth } from '@/composables/useGeminiOAuth'
 import { useAntigravityOAuth } from '@/composables/useAntigravityOAuth'
 import type { Proxy, Group, AccountPlatform, AccountType } from '@/types'
 import BaseDialog from '@/components/common/BaseDialog.vue'
+import ConfirmDialog from '@/components/common/ConfirmDialog.vue'
 import Icon from '@/components/icons/Icon.vue'
 import ProxySelector from '@/components/common/ProxySelector.vue'
 import GroupSelector from '@/components/common/GroupSelector.vue'
@@ -1760,6 +1773,11 @@ const tempUnschedEnabled = ref(false)
 const tempUnschedRules = ref<TempUnschedRuleForm[]>([])
 const geminiOAuthType = ref<'code_assist' | 'google_one' | 'ai_studio'>('google_one')
 const geminiAIStudioOAuthEnabled = ref(false)
+
+// Mixed channel warning dialog state
+const showMixedChannelWarning = ref(false)
+const mixedChannelWarningDetails = ref<{ groupName: string; currentPlatform: string; otherPlatform: string } | null>(null)
+const pendingCreatePayload = ref<any>(null)
 const showAdvancedOAuth = ref(false)
 const showGeminiHelpDialog = ref(false)
 
@@ -2158,11 +2176,7 @@ const handleClose = () => {
 }
 
 // Helper function to create account with mixed channel warning handling
-const doCreateAccount = async (payload: any, confirmMixedChannelRisk = false) => {
-  if (confirmMixedChannelRisk) {
-    payload.confirm_mixed_channel_risk = true
-  }
-  
+const doCreateAccount = async (payload: any) => {
   submitting.value = true
   try {
     await adminAPI.accounts.create(payload)
@@ -2173,22 +2187,13 @@ const doCreateAccount = async (payload: any, confirmMixedChannelRisk = false) =>
     // Handle 409 mixed_channel_warning - show confirmation dialog
     if (error.response?.status === 409 && error.response?.data?.error === 'mixed_channel_warning') {
       const details = error.response.data.details || {}
-      const groupName = details.group_name || 'Unknown'
-      const currentPlatform = details.current_platform || 'Unknown'
-      const otherPlatform = details.other_platform || 'Unknown'
-      
-      const confirmMessage = t('admin.accounts.mixedChannelWarning', {
-        groupName,
-        currentPlatform,
-        otherPlatform
-      })
-      
-      if (confirm(confirmMessage)) {
-        // Retry with confirmation flag
-        submitting.value = false
-        await doCreateAccount(payload, true)
-        return
+      mixedChannelWarningDetails.value = {
+        groupName: details.group_name || 'Unknown',
+        currentPlatform: details.current_platform || 'Unknown',
+        otherPlatform: details.other_platform || 'Unknown'
       }
+      pendingCreatePayload.value = payload
+      showMixedChannelWarning.value = true
     } else {
       appStore.showError(error.response?.data?.detail || t('admin.accounts.failedToCreate'))
     }
@@ -2197,6 +2202,32 @@ const doCreateAccount = async (payload: any, confirmMixedChannelRisk = false) =>
   }
 }
 
+// Handle mixed channel warning confirmation
+const handleMixedChannelConfirm = async () => {
+  showMixedChannelWarning.value = false
+  if (pendingCreatePayload.value) {
+    pendingCreatePayload.value.confirm_mixed_channel_risk = true
+    submitting.value = true
+    try {
+      await adminAPI.accounts.create(pendingCreatePayload.value)
+      appStore.showSuccess(t('admin.accounts.accountCreated'))
+      emit('created')
+      handleClose()
+    } catch (error: any) {
+      appStore.showError(error.response?.data?.detail || t('admin.accounts.failedToCreate'))
+    } finally {
+      submitting.value = false
+      pendingCreatePayload.value = null
+    }
+  }
+}
+
+const handleMixedChannelCancel = () => {
+  showMixedChannelWarning.value = false
+  pendingCreatePayload.value = null
+  mixedChannelWarningDetails.value = null
+}
+
 const handleSubmit = async () => {
   // For OAuth-based type, handle OAuth flow (goes to step 2)
   if (isOAuthFlow.value) {