refactor: 重构异步任务系统和计费服务架构

- 重构任务系统：新增 lifecycle (TaskStatus/BillingStatus)、context、application 模块
- 将 video tasks 泛化为 async tasks，支持更通用的异步任务管理
- 新增 Gemini Files 管理模块和管理界面
- 重构 billing 服务：拆分 schema.py 和 service.py
- 新增 candidate 服务模块用于请求候选管理
- 数据库迁移：添加 billing_status、request_id、gemini_file_mappings 表和索引
- 移除废弃的 video_telemetry、task orchestrator 等模块

frontend/src/api/async-tasks.ts

@@ -1,17 +1,21 @@
 import apiClient from './client'
 
-// 视频任务状态
-export type VideoTaskStatus = 'pending' | 'submitted' | 'queued' | 'processing' | 'completed' | 'failed' | 'cancelled'
+// 异步任务状态
+export type AsyncTaskStatus = 'pending' | 'submitted' | 'queued' | 'processing' | 'completed' | 'failed' | 'cancelled'
 
-// 视频任务列表项
-export interface VideoTaskItem {
+// 异步任务类型
+export type AsyncTaskType = 'video'
+
+// 异步任务列表项
+export interface AsyncTaskItem {
   id: string
   external_task_id: string
   user_id: string
   username: string
+  task_type: AsyncTaskType
   model: string
   prompt: string
-  status: VideoTaskStatus
+  status: AsyncTaskStatus
   progress_percent: number
   progress_message: string | null
   provider_id: string
@@ -44,7 +48,7 @@ export interface CandidateKeyInfo {
 }
 
 // 请求元数据
-export interface VideoTaskRequestMetadata {
+export interface AsyncTaskRequestMetadata {
   candidate_keys: CandidateKeyInfo[]
   selected_key_id: string
   selected_endpoint_id: string
@@ -52,10 +56,12 @@ export interface VideoTaskRequestMetadata {
   user_agent: string
   request_id: string
   request_headers?: Record<string, string>
+  poll_raw_response?: any  // 轮询完成时的原始响应
+  billing_snapshot?: any   // 计费快照
 }
 
-// 视频任务详情
-export interface VideoTaskDetail extends VideoTaskItem {
+// 异步任务详情
+export interface AsyncTaskDetail extends AsyncTaskItem {
   api_key_id: string
   endpoint_id: string
   key_id: string
@@ -81,73 +87,76 @@ export interface VideoTaskDetail extends VideoTaskItem {
     base_url: string
     api_format: string
   } | null
-  request_metadata: VideoTaskRequestMetadata | null
+  request_metadata: AsyncTaskRequestMetadata | null
 }
 
-// 视频任务列表响应
-export interface VideoTaskListResponse {
-  items: VideoTaskItem[]
+// 异步任务列表响应
+export interface AsyncTaskListResponse {
+  items: AsyncTaskItem[]
   total: number
   page: number
   page_size: number
   pages: number
 }
 
-// 视频任务统计响应
-export interface VideoTaskStatsResponse {
+// 异步任务统计响应
+export interface AsyncTaskStatsResponse {
   total: number
-  by_status: Record<VideoTaskStatus, number>
+  by_status: Record<AsyncTaskStatus, number>
   by_model: Record<string, number>
   today_count: number
   active_users?: number  // 仅管理员
   processing_count?: number  // 仅管理员
 }
 
-// 视频任务查询参数
-export interface VideoTaskQueryParams {
-  status?: VideoTaskStatus
+// 异步任务查询参数
+export interface AsyncTaskQueryParams {
+  status?: AsyncTaskStatus
+  task_type?: AsyncTaskType
   user_id?: string
   model?: string
   page?: number
   page_size?: number
 }
 
-export const videoTasksApi = {
+export const asyncTasksApi = {
   /**
-   * 获取视频任务列表
+   * 获取异步任务列表
    */
-  async list(params: VideoTaskQueryParams = {}): Promise<VideoTaskListResponse> {
+  async list(params: AsyncTaskQueryParams = {}): Promise<AsyncTaskListResponse> {
     const searchParams = new URLSearchParams()
     if (params.status) searchParams.append('status', params.status)
+    if (params.task_type) searchParams.append('task_type', params.task_type)
     if (params.user_id) searchParams.append('user_id', params.user_id)
     if (params.model) searchParams.append('model', params.model)
     if (params.page) searchParams.append('page', params.page.toString())
     if (params.page_size) searchParams.append('page_size', params.page_size.toString())
 
     const query = searchParams.toString()
+    // 后端 API 路径保持不变，前端抽象为异步任务
     const url = query ? `/api/admin/video-tasks?${query}` : '/api/admin/video-tasks'
     const response = await apiClient.get(url)
     return response.data
   },
 
   /**
-   * 获取视频任务统计
+   * 获取异步任务统计
    */
-  async getStats(): Promise<VideoTaskStatsResponse> {
+  async getStats(): Promise<AsyncTaskStatsResponse> {
     const response = await apiClient.get('/api/admin/video-tasks/stats')
     return response.data
   },
 
   /**
-   * 获取视频任务详情
+   * 获取异步任务详情
    */
-  async getDetail(taskId: string): Promise<VideoTaskDetail> {
+  async getDetail(taskId: string): Promise<AsyncTaskDetail> {
     const response = await apiClient.get(`/api/admin/video-tasks/${taskId}`)
     return response.data
   },
 
   /**
-   * 取消视频任务
+   * 取消异步任务
    */
   async cancel(taskId: string): Promise<{ id: string; status: string; message: string }> {
     const response = await apiClient.post(`/api/admin/video-tasks/${taskId}/cancel`)
@@ -155,4 +164,4 @@ export const videoTasksApi = {
   },
 }
 
-export default videoTasksApi
+export default asyncTasksApi

frontend/src/api/endpoints/types.ts

@@ -340,6 +340,7 @@ export interface ProviderWithEndpointsSummary {
   website?: string
   provider_priority: number
   keep_priority_on_conversion: boolean  // 格式转换时是否保持优先级
+  enable_format_conversion: boolean  // 是否允许格式转换（提供商级别开关）
   billing_type?: 'monthly_quota' | 'pay_as_you_go' | 'free_tier'
   monthly_quota_usd?: number
   monthly_used_usd?: number

frontend/src/api/gemini-files.ts

@@ -0,0 +1,124 @@
+/**
+ * Gemini Files 管理 API
+ */
+
+import apiClient from './client'
+
+export interface FileMappingResponse {
+  id: string
+  file_name: string
+  key_id: string
+  key_name: string | null
+  user_id: string | null
+  username: string | null
+  display_name: string | null
+  mime_type: string | null
+  created_at: string
+  expires_at: string
+  is_expired: boolean
+}
+
+export interface FileMappingListResponse {
+  items: FileMappingResponse[]
+  total: number
+  page: number
+  page_size: number
+}
+
+export interface FileMappingStatsResponse {
+  total_mappings: number
+  active_mappings: number
+  expired_mappings: number
+  by_mime_type: Record<string, number>
+  capable_keys_count: number
+}
+
+export interface ListMappingsParams {
+  page?: number
+  page_size?: number
+  include_expired?: boolean
+  search?: string
+}
+
+export interface CapableKeyResponse {
+  id: string
+  name: string
+  provider_name: string | null
+}
+
+export interface UploadResultItem {
+  key_id: string
+  key_name: string | null
+  success: boolean
+  file_name: string | null
+  error: string | null
+}
+
+export interface UploadResponse {
+  display_name: string
+  mime_type: string
+  size_bytes: number
+  results: UploadResultItem[]
+  success_count: number
+  fail_count: number
+}
+
+export const geminiFilesApi = {
+  /**
+   * 获取文件映射统计
+   */
+  async getStats(): Promise<FileMappingStatsResponse> {
+    const response = await apiClient.get('/api/admin/gemini-files/stats')
+    return response.data
+  },
+
+  /**
+   * 列出文件映射
+   */
+  async listMappings(params?: ListMappingsParams): Promise<FileMappingListResponse> {
+    const response = await apiClient.get('/api/admin/gemini-files/mappings', { params })
+    return response.data
+  },
+
+  /**
+   * 删除指定映射
+   */
+  async deleteMapping(mappingId: string): Promise<{ message: string; file_name: string }> {
+    const response = await apiClient.delete(`/api/admin/gemini-files/mappings/${mappingId}`)
+    return response.data
+  },
+
+  /**
+   * 清理过期映射
+   */
+  async cleanupExpired(): Promise<{ message: string; deleted_count: number }> {
+    const response = await apiClient.delete('/api/admin/gemini-files/mappings')
+    return response.data
+  },
+
+  /**
+   * 获取可用的 Key 列表
+   */
+  async getCapableKeys(): Promise<CapableKeyResponse[]> {
+    const response = await apiClient.get('/api/admin/gemini-files/capable-keys')
+    return response.data
+  },
+
+  /**
+   * 上传文件到指定的 Keys
+   */
+  async uploadFile(file: File, keyIds: string[]): Promise<UploadResponse> {
+    const formData = new FormData()
+    formData.append('file', file)
+    const response = await apiClient.post(
+      `/api/admin/gemini-files/upload?key_ids=${keyIds.join(',')}`,
+      formData,
+      {
+        headers: {
+          'Content-Type': 'multipart/form-data'
+        }
+      }
+    )
+    return response.data
+  }
+}