refactor(storage): move file management routes from user to admin namespace

- Remove file list, stats, download, and deletion routes from '/api/v1/upload'
- Move these endpoints under '/api/v1/admin/uploads'
- Remove user-specific filtering from files query and statistics to aggregate system-wide uploads by default
- Allow admins to bypass ownership check when downloading private files
- Update backend unit tests, Swagger documentation, and frontend service client and components

frontend/components/common/admin/file-list.tsx

@@ -80,8 +80,8 @@ export function FileList() {
 
   // 文件列表查询
   const listQuery = useQuery({
-    queryKey: ["files", "my", page, pageSize, debouncedKeyword],
-    queryFn: () => UploadService.listMyFiles(page, pageSize, debouncedKeyword || undefined),
+    queryKey: ["files", "all", page, pageSize, debouncedKeyword],
+    queryFn: () => UploadService.listUploads(page, pageSize, debouncedKeyword || undefined),
   })
 
   const files = listQuery.data?.items ?? []