refactor: 统一 API 格式显示函数，补全 Usage/Trace 的 provider 链路信息

- 提取 formatApiFormat 为共享工具函数，替换各组件中分散的 API_FORMAT_LABELS 调用
- Trace API 返回密钥认证类型(key_auth_type)和 OAuth 套餐信息(key_oauth_plan_type)
- 请求时间线展示密钥认证方式标签（OAuth/Vertex AI/Kiro 等）
- Usage 记录补充 provider_id/endpoint_id/key_id，避免 curl 复现时缺失 provider 信息
- curl 复现兜底从 RequestCandidate 表查找 provider 信息
- Headers Diff 面板左右独立滚动并同步垂直滚动位置

frontend/src/features/usage/components/RequestDetailDrawer.vue

@@ -640,7 +640,7 @@ import Tabs from '@/components/ui/tabs.vue'
 import TabsContent from '@/components/ui/tabs-content.vue'
 import { Copy, Check, Maximize2, Minimize2, Columns2, RefreshCw, X, Monitor, Server, MessageSquareText, Code2, Terminal, Play } from 'lucide-vue-next'
 import { dashboardApi, type RequestDetail } from '@/api/dashboard'
-import { API_FORMAT_LABELS } from '@/api/endpoints/types'
+import { formatApiFormat } from '@/api/endpoints/types/api-format'
 import { log } from '@/utils/logger'
 
 // 子组件
@@ -1074,17 +1074,6 @@ function getTaskTypeLabel(taskType: string): string {
   }
 }
 
-function formatApiFormat(format: string | null | undefined): string {
-  if (!format) return '-'
-  const raw = (format || '').trim()
-  return (
-    API_FORMAT_LABELS[raw] ||
-    API_FORMAT_LABELS[raw.toLowerCase()] ||
-    API_FORMAT_LABELS[raw.toUpperCase()] ||
-    raw
-  )
-}
-
 function formatNumber(num: number): string {
   if (num >= 1_000_000) {
     return `${(num / 1_000_000).toFixed(1)  }M`