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/storage/local.go

@@ -167,3 +167,82 @@ func (s *LocalStore) ListReleases(runtimeVersion string) ([]model.ReleaseInfo, e
 	return out, nil
 }
 
+func (s *LocalStore) SaveAPK(runtimeVersion string, reader io.Reader) (string, error) {
+	apkDir := filepath.Join(s.root, "apk")
+	if err := os.MkdirAll(apkDir, 0o755); err != nil {
+		return "", err
+	}
+	filename := fmt.Sprintf("%s.apk", runtimeVersion)
+	apkPath := filepath.Join(apkDir, filename)
+	tmpPath := apkPath + ".tmp"
+
+	f, err := os.Create(tmpPath)
+	if err != nil {
+		return "", err
+	}
+
+	_, copyErr := io.Copy(f, reader)
+	syncErr := f.Sync()
+	closeErr := f.Close()
+
+	if copyErr != nil {
+		os.Remove(tmpPath)
+		return "", copyErr
+	}
+	if syncErr != nil {
+		os.Remove(tmpPath)
+		return "", syncErr
+	}
+	if closeErr != nil {
+		os.Remove(tmpPath)
+		return "", closeErr
+	}
+	if err := os.Rename(tmpPath, apkPath); err != nil {
+		os.Remove(tmpPath)
+		return "", err
+	}
+	return apkPath, nil
+}
+
+func (s *LocalStore) GetAPKPath(runtimeVersion string) (string, error) {
+	filename := fmt.Sprintf("%s.apk", runtimeVersion)
+	apkPath := filepath.Join(s.root, "apk", filename)
+	if _, err := os.Stat(apkPath); err != nil {
+		return "", err
+	}
+	return apkPath, nil
+}
+
+func (s *LocalStore) ListAPKs() ([]model.APKInfo, error) {
+	apkDir := filepath.Join(s.root, "apk")
+	if _, err := os.Stat(apkDir); err != nil {
+		if os.IsNotExist(err) {
+			return []model.APKInfo{}, nil
+		}
+		return nil, err
+	}
+	entries, err := os.ReadDir(apkDir)
+	if err != nil {
+		return nil, err
+	}
+	out := make([]model.APKInfo, 0, len(entries))
+	for _, e := range entries {
+		if e.IsDir() || !strings.HasSuffix(e.Name(), ".apk") {
+			continue
+		}
+		runtimeVersion := strings.TrimSuffix(e.Name(), ".apk")
+		full := filepath.Join(apkDir, e.Name())
+		fi, err := os.Stat(full)
+		if err != nil {
+			continue
+		}
+		out = append(out, model.APKInfo{
+			RuntimeVersion: runtimeVersion,
+			Path:           full,
+			Size:           fi.Size(),
+			CreatedAt:      fi.ModTime(),
+		})
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].RuntimeVersion > out[j].RuntimeVersion })
+	return out, nil
+}