Show Space Engineers build ID and last update time in detail view

Reads the SteamCMD appmanifest_298740.acf via SSH and exposes
buildid + LastUpdated through a new /api/servers/:id/version endpoint.
The overview tab now renders a "Server Version" card and surfaces a
pending update hint when TargetBuildID differs from the installed build.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

gsm-backend/services/serverVersions.js

@@ -0,0 +1,75 @@
+import { NodeSSH } from "node-ssh";
+
+const SSH_TIMEOUT = 15000;
+const sshConnections = new Map();
+
+async function getConnection(host, username = "root") {
+  const key = username + "@" + host;
+  if (sshConnections.has(key)) {
+    const conn = sshConnections.get(key);
+    if (conn.isConnected()) return conn;
+    sshConnections.delete(key);
+  }
+  const ssh = new NodeSSH();
+  await ssh.connect({
+    host,
+    username,
+    privateKeyPath: "/root/.ssh/id_ed25519",
+    readyTimeout: SSH_TIMEOUT
+  });
+  sshConnections.set(key, ssh);
+  return ssh;
+}
+
+const SE_APPMANIFEST = "/opt/spaceengineers/appdata/space-engineers/bins/SpaceEngineersDedicated/steamapps/appmanifest_298740.acf";
+
+async function getSpaceEngineersVersion(server) {
+  const ssh = await getConnection(server.host, server.sshUser);
+  const result = await ssh.execCommand(`cat ${SE_APPMANIFEST} 2>/dev/null`);
+  const text = result.stdout || "";
+  if (!text) return null;
+
+  const buildidMatch = text.match(/"buildid"\s*"([^"]+)"/);
+  const lastUpdatedMatch = text.match(/"LastUpdated"\s*"([^"]+)"/);
+  const targetBuildMatch = text.match(/"TargetBuildID"\s*"([^"]+)"/);
+
+  const buildid = buildidMatch ? buildidMatch[1] : null;
+  const lastUpdatedUnix = lastUpdatedMatch ? parseInt(lastUpdatedMatch[1], 10) : null;
+  const targetBuild = targetBuildMatch ? targetBuildMatch[1] : null;
+
+  if (!buildid) return null;
+
+  return {
+    version: buildid,
+    lastUpdated: lastUpdatedUnix ? new Date(lastUpdatedUnix * 1000).toISOString() : null,
+    updatePending: targetBuild && targetBuild !== "0" && targetBuild !== buildid ? targetBuild : null,
+    source: "steam-appmanifest"
+  };
+}
+
+const versionHandlers = {
+  spaceengineers: getSpaceEngineersVersion
+};
+
+const versionCache = new Map();
+const CACHE_TTL_MS = 60_000;
+
+export function supportsVersionInfo(serverType) {
+  return !!versionHandlers[serverType];
+}
+
+export async function getVersionInfo(server) {
+  const handler = versionHandlers[server.type];
+  if (!handler) return null;
+
+  const cached = versionCache.get(server.id);
+  if (cached && Date.now() - cached.fetchedAt < CACHE_TTL_MS) {
+    return cached.data;
+  }
+
+  const data = await handler(server);
+  if (data) {
+    versionCache.set(server.id, { data, fetchedAt: Date.now() });
+  }
+  return data;
+}