feat(server): 自动更新 /version 清单端点(镜像 jiu)

GET /version(公开)读 /etc/pangolin/version.yaml(每请求重载,免重启);缺省回退。
download_urls 接 /downloads。deploy.sh 装清单(存在则不覆盖, 保住线上 bump)。含 4 测试。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013nMthbVEmQquxBRKb9Fj8u

server/cmd/server/main.go

@@ -138,6 +138,13 @@ func main() {
 	downloadsHandler := httpapi.NewDownloadsHandler(os.Getenv("DOWNLOADS_DIR"))
 	r.Get("/downloads/*", downloadsHandler.Serve)
 
+	// Public (no auth): 客户端自动更新版本清单。VERSION_MANIFEST 可配置清单路径
+	// (默认 /etc/pangolin/version.yaml);deploy/single-node/deploy.sh 安装仓库内
+	// 默认清单,scripts/ci/release-client.sh 在每次 client-v* 发版时改写其
+	// version/build_number。每次请求都重新读文件,发版脚本改完立即生效,无需重启。
+	versionHandler := httpapi.NewVersionHandler(os.Getenv("VERSION_MANIFEST"))
+	r.Get("/version", versionHandler.Serve)
+
 	// Optional probe ingest route. sharedProbeStore is reused by the scheduler
 	// (below) when both are enabled, so they share one Redis-backed store.
 	var sharedProbeStore *probe.Store