feat(admin): 添加APK管理功能

实现APK文件的上传、下载和列表功能
- 新增APKInfo数据结构
- 添加/admin/apk/upload、/admin/apk/download和/admin/apk/list路由
- 实现APK存储服务方法
- 添加相关测试用例

internal/app/server.go

@@ -35,7 +35,9 @@ func (s *Server) Routes() http.Handler {
 	mux.HandleFunc("/admin/publish", s.handlers.AdminPublish)
 	mux.HandleFunc("/admin/rollback", s.handlers.AdminRollback)
 	mux.HandleFunc("/admin/releases", s.handlers.AdminReleases)
+	mux.HandleFunc("/admin/apk/upload", s.handlers.AdminUploadAPK)
+	mux.HandleFunc("/admin/apk/download", s.handlers.AdminDownloadAPK)
+	mux.HandleFunc("/admin/apk/list", s.handlers.AdminListAPKs)
 	mux.HandleFunc("/healthz", s.handlers.Healthz)
 	return mux
 }
-