Add graceful SCUM stop, restart, and version update flow

SCUM 停止/重启/更新以前只有“结束进程”这一条路，插件没有声明任何优雅关闭方式，
平台也没有把停止后重新启动串起来。现在插件声明自己的关闭脚本，run 先执行它，
平台在停止或更新成功后再自动拉起服务。

run:
- lifecycle stop 支持插件声明的 gracefulStop（可执行文件、参数、环境、超时、
  fallback=report|terminate）；关闭命令超时且声明 report 时任务失败，不再默默杀进程。
- 新增 steam.update 依赖探针：调用 steamcmd +app_info_print 获取公开分支 buildid，
  与本地 steamapps/appmanifest_<appid>.acf 的 buildid 比较，输出
  installed/latest/update=yes|no|unknown。

platform:
- 新增 POST /api/v1/server-instances/{id}/restart 与 /update。
- restart 派发插件 stop 动作（走优雅关闭），终态成功后入队 start 作业。
- update 派发插件 install 动作；插件在更新前必须先优雅关闭 SCUM，关闭失败直接拒绝
  SteamCMD 更新，成功后平台再拉起服务。
- 依赖检查输入带上插件声明的服务器安装根目录，供 steam.update 读取 appmanifest。

plugin (SCUM server plugin 0.1.16):
- bin/scum-stop.cmd：解析已声明的可执行文件路径，定位同路径正在运行的 SCUMServer.exe，
  通过本地 RCON 公告并发送关闭命令，等待进程自行退出；不再使用 taskkill。
- bin/scum-rcon.ps1：插件自有的 Source RCON 客户端，从 UE4SS mod config.ini 读取
  密码/端口，密钥不离开本机。
- actions/stop.json 声明 gracefulStop；actions/install.json 更新前先执行同一关闭脚本。

platform_web:
- 服务器详情新增“重启”按钮和“SCUM 版本更新”面板；点“检查更新”查询公开分支版本，
  只有检测到更新时“更新版本”按钮才会置为可用并高亮，点击后先确认再派发更新任务。

platform/service/server_lifecycle.go

@@ -212,6 +212,34 @@ func (svc *CoreService) StopServerInstanceForSession(sessionID string, command d
 	return svc.StopServerInstance(command)
 }
 
+// RestartServerInstanceForSession queues the plugin-declared graceful stop and
+// records restart intent. Run executes the stop action; the terminal stop
+// result dispatches the plugin-declared start action for the same instance.
+func (svc *CoreService) RestartServerInstanceForSession(sessionID string, command domain.ServerLifecycleCommand) (domain.ServerLifecycleResult, error) {
+	if err := svc.authorizeServerLifecycle(sessionID, command.ServerInstanceID); err != nil {
+		return domain.ServerLifecycleResult{}, err
+	}
+	return svc.dispatchExistingServerLifecycle(command, domain.ServerLifecycleActionRestart, []domain.ServerInstanceState{
+		domain.ServerInstanceStateRunning,
+		domain.ServerInstanceStateStopped,
+	})
+}
+
+// UpdateServerGameForSession queues the plugin-declared install/update action.
+// The plugin script stops the running server gracefully before SteamCMD touches
+// server files, and the terminal update result starts the server again.
+func (svc *CoreService) UpdateServerGameForSession(sessionID string, command domain.ServerLifecycleCommand) (domain.ServerLifecycleResult, error) {
+	if err := svc.authorizeServerLifecycle(sessionID, command.ServerInstanceID); err != nil {
+		return domain.ServerLifecycleResult{}, err
+	}
+	return svc.dispatchExistingServerLifecycle(command, domain.ServerLifecycleActionUpdate, []domain.ServerInstanceState{
+		domain.ServerInstanceStateRunning,
+		domain.ServerInstanceStateStopped,
+		domain.ServerInstanceStateReady,
+		domain.ServerInstanceStateFailed,
+	})
+}
+
 func (svc *CoreService) QueryServerInstanceProcessForSession(sessionID string, command domain.ServerLifecycleCommand) (domain.ServerLifecycleResult, error) {
 	if err := svc.authorizeServerLifecycle(sessionID, command.ServerInstanceID); err != nil {
 		return domain.ServerLifecycleResult{}, err
@@ -418,6 +446,10 @@ func lifecycleExecutionOperation(action domain.ServerLifecycleAction) string {
 		return "start"
 	case domain.ServerLifecycleActionStop:
 		return "stop"
+	case domain.ServerLifecycleActionRestart:
+		return "restart"
+	case domain.ServerLifecycleActionUpdate:
+		return "update"
 	case domain.ServerLifecycleActionStatus:
 		return "status"
 	default:
@@ -431,8 +463,10 @@ func runtimeProfileActionRef(actions domain.PluginLifecycleActions, action domai
 		return actions.Install
 	case domain.ServerLifecycleActionStart:
 		return actions.Start
-	case domain.ServerLifecycleActionStop:
+	case domain.ServerLifecycleActionStop, domain.ServerLifecycleActionRestart:
 		return actions.Stop
+	case domain.ServerLifecycleActionUpdate:
+		return actions.Install
 	case domain.ServerLifecycleActionStatus:
 		return actions.Status
 	default:
@@ -502,8 +536,10 @@ func lifecycleActionRef(plugin domain.GamePlugin, action domain.ServerLifecycleA
 		return plugin.LifecycleActions.Install
 	case domain.ServerLifecycleActionStart:
 		return plugin.LifecycleActions.Start
-	case domain.ServerLifecycleActionStop:
+	case domain.ServerLifecycleActionStop, domain.ServerLifecycleActionRestart:
 		return plugin.LifecycleActions.Stop
+	case domain.ServerLifecycleActionUpdate:
+		return plugin.LifecycleActions.Install
 	case domain.ServerLifecycleActionStatus:
 		return plugin.LifecycleActions.Status
 	default: