fix(providers): 修复 Key 表单状态同步与 streaming 候选状态码处理

前端:
- KeyAllowedModelsEditDialog 同时监听 open 和 apiKey 变化，避免切换 key 时状态未刷新
- KeyFormDialog 新增 api_formats 过滤与默认值逻辑，可用格式变化时自动同步表单
- ProviderDetailDrawer 合并 provider 和 endpoint 的 api_formats 传递给 Key 表单，
  数据刷新后同步 currentEndpoint 和 editingKey 引用

后端:
- mark_candidate_streaming 移除 status_code 参数，streaming 阶段不再提前写入状态码
- 简化 active_requests 中 streaming 请求的完成判断，不再依赖 status_code 条件

frontend/src/features/providers/components/ProviderDetailDrawer.vue

@@ -936,7 +936,7 @@
     :editing-key="editingKey"
     :provider-id="provider ? provider.id : null"
     :provider-type="provider?.provider_type || null"
-    :available-api-formats="provider?.api_formats || []"
+    :available-api-formats="availableKeyApiFormats"
     @close="keyFormDialogOpen = false"
     @saved="handleKeyChanged"
   />
@@ -1258,6 +1258,65 @@ const allKeys = computed(() => {
   return result
 })
 
+const availableKeyApiFormats = computed(() => {
+  const formatSet = new Set<string>()
+
+  for (const format of provider.value?.api_formats || []) {
+    if (format) {
+      formatSet.add(format)
+    }
+  }
+
+  for (const endpoint of endpoints.value) {
+    if (endpoint.api_format) {
+      formatSet.add(endpoint.api_format)
+    }
+  }
+
+  return sortApiFormats([...formatSet])
+})
+
+function syncCurrentSelections(
+  nextEndpoints: ProviderEndpointWithKeys[] = endpoints.value,
+  nextProviderKeys: EndpointAPIKey[] = providerKeys.value
+) {
+  if (currentEndpoint.value) {
+    currentEndpoint.value = nextEndpoints.find(endpoint => endpoint.id === currentEndpoint.value?.id) ?? null
+  }
+
+  if (!editingKey.value) {
+    return
+  }
+
+  const latestKeys: EndpointAPIKey[] = []
+  const seenKeyIds = new Set<string>()
+
+  for (const key of nextProviderKeys) {
+    if (!seenKeyIds.has(key.id)) {
+      seenKeyIds.add(key.id)
+      latestKeys.push(key)
+    }
+  }
+
+  for (const endpoint of nextEndpoints) {
+    for (const key of endpoint.keys || []) {
+      if (!seenKeyIds.has(key.id)) {
+        seenKeyIds.add(key.id)
+        latestKeys.push(key)
+      }
+    }
+  }
+
+  const latestEditingKey = latestKeys.find(key => key.id === editingKey.value?.id) || null
+  editingKey.value = latestEditingKey
+
+  if (!latestEditingKey) {
+    keyFormDialogOpen.value = false
+    keyPermissionsDialogOpen.value = false
+    oauthKeyEditDialogOpen.value = false
+  }
+}
+
 // ===== 账号列表智能分页 =====
 const keysListRef = ref<HTMLElement | null>(null)
 const {
@@ -1558,6 +1617,7 @@ async function handleRefreshOAuth(key: EndpointAPIKey) {
       const freshKeys = await getProviderKeys(props.providerId).catch(() => null)
       if (freshKeys) {
         providerKeys.value = freshKeys
+        syncCurrentSelections(endpoints.value, freshKeys)
       }
     }
     // Antigravity：token 刷新后可能完成了账号激活，触发配额获取
@@ -2640,7 +2700,7 @@ async function loadEndpoints() {
     providerKeys.value = providerKeysResult
     providerModels.value = modelsResult
     // 按 API 格式排序
-    endpoints.value = endpointsList.sort((a, b) => {
+    const sortedEndpoints = endpointsList.sort((a, b) => {
       const aIdx = API_FORMAT_ORDER.indexOf(a.api_format)
       const bIdx = API_FORMAT_ORDER.indexOf(b.api_format)
       if (aIdx === -1 && bIdx === -1) return 0
@@ -2648,6 +2708,8 @@ async function loadEndpoints() {
       if (bIdx === -1) return -1
       return aIdx - bIdx
     })
+    endpoints.value = sortedEndpoints
+    syncCurrentSelections(sortedEndpoints, providerKeysResult)
   } catch (err: unknown) {
     if (requestId !== endpointsLoadRequestId) return
     showError(parseApiError(err, '加载端点失败'), '错误')