fix: bulk edit mixed channel warning not showing confirmation dialog

The response interceptor in client.ts transforms errors into plain
objects {status, code, message}, but catch blocks were checking
error.response?.status (AxiosError format) which never matched.

- Add error field passthrough in client.ts interceptor
- Refactor BulkEditAccountModal to use pre-check API (checkMixedChannelRisk)
  before submit, matching the single edit flow
- Fix EditAccountModal catch blocks to use interceptor error format
- Add bulk-update mixed channel unit tests

frontend/src/api/client.ts

@@ -267,6 +267,7 @@ apiClient.interceptors.response.use(
       return Promise.reject({
         status,
         code: apiData.code,
+        error: apiData.error,
         message: apiData.message || apiData.detail || error.message
       })
     }

frontend/src/components/account/BulkEditAccountModal.vue

@@ -1252,14 +1252,43 @@ const buildUpdatePayload = (): Record<string, unknown> | null => {
   return Object.keys(updates).length > 0 ? updates : null
 }
 
+const mixedChannelConfirmed = ref(false)
+
+const needsMixedChannelCheck = () =>
+  enableGroups.value &&
+  props.selectedPlatforms.length === 1 &&
+  (props.selectedPlatforms[0] === 'antigravity' || props.selectedPlatforms[0] === 'anthropic')
+
 const handleClose = () => {
   showMixedChannelWarning.value = false
   mixedChannelWarningMessage.value = ''
   pendingUpdatesForConfirm.value = null
+  mixedChannelConfirmed.value = false
   emit('close')
 }
 
-const handleSubmit = async (confirmMixedChannel = false) => {
+const checkMixedChannelRisk = async (): Promise<boolean> => {
+  if (!needsMixedChannelCheck()) return true
+  if (mixedChannelConfirmed.value) return true
+  if (groupIds.value.length === 0) return true
+
+  try {
+    const result = await adminAPI.accounts.checkMixedChannelRisk({
+      platform: props.selectedPlatforms[0],
+      group_ids: groupIds.value
+    })
+    if (!result.has_risk) return true
+
+    mixedChannelWarningMessage.value = result.message || t('admin.accounts.bulkEdit.failed')
+    showMixedChannelWarning.value = true
+    return false
+  } catch (error: any) {
+    appStore.showError(error.message || t('admin.accounts.bulkEdit.failed'))
+    return false
+  }
+}
+
+const handleSubmit = async () => {
   if (props.accountIds.length === 0) {
     appStore.showError(t('admin.accounts.bulkEdit.noSelection'))
     return
@@ -1283,16 +1312,24 @@ const handleSubmit = async (confirmMixedChannel = false) => {
     return
   }
 
-  let updates: Record<string, unknown>
-  if (confirmMixedChannel && pendingUpdatesForConfirm.value) {
-    updates = { ...pendingUpdatesForConfirm.value, confirm_mixed_channel_risk: true }
-  } else {
-    const built = buildUpdatePayload()
-    if (!built) {
-      appStore.showError(t('admin.accounts.bulkEdit.noFieldsSelected'))
-      return
-    }
-    updates = built
+  const built = buildUpdatePayload()
+  if (!built) {
+    appStore.showError(t('admin.accounts.bulkEdit.noFieldsSelected'))
+    return
+  }
+
+  const canContinue = await checkMixedChannelRisk()
+  if (!canContinue) {
+    pendingUpdatesForConfirm.value = built
+    return
+  }
+
+  await submitBulkUpdate(built)
+}
+
+const submitBulkUpdate = async (updates: Record<string, unknown>) => {
+  if (mixedChannelConfirmed.value && needsMixedChannelCheck()) {
+    updates = { ...updates, confirm_mixed_channel_risk: true }
   }
 
   submitting.value = true
@@ -1316,14 +1353,8 @@ const handleSubmit = async (confirmMixedChannel = false) => {
       handleClose()
     }
   } catch (error: any) {
-    if (error.response?.status === 409 && error.response?.data?.error === 'mixed_channel_warning') {
-      pendingUpdatesForConfirm.value = updates
-      mixedChannelWarningMessage.value = error.response.data.message
-      showMixedChannelWarning.value = true
-    } else {
-      appStore.showError(error.response?.data?.detail || t('admin.accounts.bulkEdit.failed'))
-      console.error('Error bulk updating accounts:', error)
-    }
+    appStore.showError(error.message || t('admin.accounts.bulkEdit.failed'))
+    console.error('Error bulk updating accounts:', error)
   } finally {
     submitting.value = false
   }
@@ -1331,7 +1362,10 @@ const handleSubmit = async (confirmMixedChannel = false) => {
 
 const handleMixedChannelConfirm = async () => {
   showMixedChannelWarning.value = false
-  await handleSubmit(true)
+  mixedChannelConfirmed.value = true
+  if (pendingUpdatesForConfirm.value) {
+    await submitBulkUpdate(pendingUpdatesForConfirm.value)
+  }
 }
 
 const handleMixedChannelCancel = () => {
@@ -1376,6 +1410,7 @@ watch(
       showMixedChannelWarning.value = false
       mixedChannelWarningMessage.value = ''
       pendingUpdatesForConfirm.value = null
+      mixedChannelConfirmed.value = false
     }
   }
 )

frontend/src/components/account/EditAccountModal.vue

@@ -1961,7 +1961,7 @@ const ensureAntigravityMixedChannelConfirmed = async (onConfirm: () => Promise<v
     })
     return false
   } catch (error: any) {
-    appStore.showError(error.response?.data?.message || error.response?.data?.detail || t('admin.accounts.failedToUpdate'))
+    appStore.showError(error.message || t('admin.accounts.failedToUpdate'))
     return false
   }
 }
@@ -1984,9 +1984,9 @@ const submitUpdateAccount = async (accountID: number, updatePayload: Record<stri
     emit('updated', updatedAccount)
     handleClose()
   } catch (error: any) {
-    if (error.response?.status === 409 && error.response?.data?.error === 'mixed_channel_warning' && needsMixedChannelCheck()) {
+    if (error.status === 409 && error.error === 'mixed_channel_warning' && needsMixedChannelCheck()) {
       openMixedChannelDialog({
-        message: error.response?.data?.message,
+        message: error.message,
         onConfirm: async () => {
           antigravityMixedChannelConfirmed.value = true
           await submitUpdateAccount(accountID, updatePayload)
@@ -1994,7 +1994,7 @@ const submitUpdateAccount = async (accountID: number, updatePayload: Record<stri
       })
       return
     }
-    appStore.showError(error.response?.data?.message || error.response?.data?.detail || t('admin.accounts.failedToUpdate'))
+    appStore.showError(error.message || t('admin.accounts.failedToUpdate'))
   } finally {
     submitting.value = false
   }
@@ -2245,7 +2245,7 @@ const handleSubmit = async () => {
 
     await submitUpdateAccount(accountID, updatePayload)
   } catch (error: any) {
-    appStore.showError(error.response?.data?.message || error.response?.data?.detail || t('admin.accounts.failedToUpdate'))
+    appStore.showError(error.message || t('admin.accounts.failedToUpdate'))
   }
 }