feat(apk): 增加公开APK管理接口和CI/CD工作流

- 新增获取最新APK版本信息和下载APK的公开接口
- 更新README文档，添加APK管理接口的使用说明
- 实现CI/CD工作流，支持自动构建和部署
- 优化APK存储逻辑，确保只保留最新APK文件

internal/service/update_service.go

@@ -56,6 +56,10 @@ func NewUpdateService(store *storage.LocalStore, hostname string, privateKeyPath
 	return &UpdateService{store: store, hostname: hostname, privateKeyPath: privateKeyPath}
 }
 
+func (s *UpdateService) Hostname() string {
+	return s.hostname
+}
+
 func (s *UpdateService) PublishZip(runtimeVersion string, platform string, zipReader *bytes.Reader, size int64) (string, error) {
 	return s.store.PublishZip(runtimeVersion, platform, zipReader, size)
 }
@@ -80,6 +84,10 @@ func (s *UpdateService) ListAPKs() ([]model.APKInfo, error) {
 	return s.store.ListAPKs()
 }
 
+func (s *UpdateService) GetLatestAPK() (*model.APKInfo, error) {
+	return s.store.GetLatestAPK()
+}
+
 func (s *UpdateService) BuildManifestResponse(req ManifestRequest) (ManifestResponse, error) {
 	releasePath, err := s.store.LatestReleasePath(req.RuntimeVersion, req.Platform)
 	if err != nil {