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_web/contracts/serverManagement.test.ts

@@ -1,7 +1,7 @@
 import { describe, expect, it } from "vitest";
 
-import { canStartServer, canStopServer, runtimeObservationFreshness } from "./serverManagement";
-import type { RunEndpointResponse, ServerInstanceResponse, ServerInstanceState } from "../api/types";
+import { canRestartServer, canStartServer, canStopServer, canUpdateServerGame, gameUpdateStatusFromProbe, gameUpdateStatusLabel, steamUpdateProbe, runtimeObservationFreshness } from "./serverManagement";
+import type { DependencyCatalogResponse, DependencyProbeViewResponse, RunEndpointResponse, ServerInstanceResponse, ServerInstanceState } from "../api/types";
 
 describe("server management lifecycle contracts", () => {
   it("allows explicit starts from recoverable non-running states", () => {
@@ -17,6 +17,41 @@ describe("server management lifecycle contracts", () => {
     expect(canStopServer("failed")).toBe(false);
   });
 
+  it("keeps restart and update dispatch inside the states the platform accepts", () => {
+    const restartable: ServerInstanceState[] = ["running", "stopped"];
+    const updatable: ServerInstanceState[] = ["running", "stopped", "ready", "failed"];
+    expect(restartable.every(canRestartServer)).toBe(true);
+    expect((["draft", "installing", "ready", "failed", "deleted"] as ServerInstanceState[]).some(canRestartServer)).toBe(false);
+    expect(updatable.every(canUpdateServerGame)).toBe(true);
+    expect((["draft", "installing", "deleted"] as ServerInstanceState[]).some(canUpdateServerGame)).toBe(false);
+  });
+
+  it("reads the Steam build probe evidence into an update decision", () => {
+    const catalog = {
+      serverInstanceId: "server-1",
+      pluginId: "game.scum",
+      pluginVersion: "0.1.16",
+      profileKey: "run-local",
+      targetOs: "windows",
+      targetArch: "amd64",
+      updatedAt: "2026-09-15T00:00:00Z",
+      plans: [],
+      probes: [{ key: "scum-server-build", kind: "steam.update", required: false, state: "present", evidence: "installed=100 latest=200 update=yes" }]
+    } as DependencyCatalogResponse;
+    const probe = steamUpdateProbe(catalog);
+    expect(probe?.key).toBe("scum-server-build");
+    const status = gameUpdateStatusFromProbe(probe);
+    expect(status).toEqual({ availability: "available", installed: "100", latest: "200" });
+    expect(gameUpdateStatusLabel(status)).toBe("发现新版本");
+
+    const current = gameUpdateStatusFromProbe({ ...probe, evidence: "installed=200 latest=200 update=no" } as DependencyProbeViewResponse);
+    expect(current?.availability).toBe("up-to-date");
+    const unknown = gameUpdateStatusFromProbe({ ...probe, evidence: "installed=none latest=200 update=yes" } as DependencyProbeViewResponse);
+    expect(unknown).toEqual({ availability: "available", installed: "none", latest: "200" });
+    const missing = gameUpdateStatusFromProbe({ ...probe, kind: "java.version" } as DependencyProbeViewResponse);
+    expect(missing).toBeUndefined();
+  });
+
   it("distinguishes a fresh Run observation from an unverified historical lifecycle state", () => {
     const instance = { id: "server-1", state: "running", runEndpointId: "run-1" } as ServerInstanceResponse;
     const endpoint = { id: "run-1", status: "online", lastHeartbeatAt: "2026-08-07T10:00:00Z" } as RunEndpointResponse;