Add Hytale config editor and Prometheus integration

- Add Node Exporter target for Hytale server (10.0.30.204:9100)
- Add Hytale config read/write functions to ssh.js
- Add GET/PUT /hytale/config API routes
- Create HytaleConfigEditor.jsx with JSON syntax highlighting
- Add Hytale config tab to ServerDetail.jsx
- Add stopCmd and port to Hytale server config

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

gsm-backend/services/ssh.js

@@ -642,3 +642,30 @@ export async function writeOpenTTDConfig(server, content) {
   await ssh.execCommand(`ls -t /opt/openttd/.openttd/openttd.cfg.backup.* 2>/dev/null | tail -n +6 | xargs rm -f 2>/dev/null || true`);
   return true;
 }
+
+// Hytale Config Management
+const HYTALE_CONFIG_PATH = "/opt/hytale/Server/config.json";
+
+export async function readHytaleConfig(server) {
+  const ssh = await getConnection(server.host, server.sshUser);
+  const result = await ssh.execCommand(`cat ${HYTALE_CONFIG_PATH}`);
+  if (result.code !== 0) {
+    throw new Error(result.stderr || "Failed to read config file");
+  }
+  return result.stdout;
+}
+
+export async function writeHytaleConfig(server, content) {
+  const ssh = await getConnection(server.host, server.sshUser);
+  const backupName = `config.json.backup.${Date.now()}`;
+  await ssh.execCommand(`cp ${HYTALE_CONFIG_PATH} /opt/hytale/Server/${backupName} 2>/dev/null || true`);
+  const sftp = await ssh.requestSFTP();
+  await new Promise((resolve, reject) => {
+    sftp.writeFile(HYTALE_CONFIG_PATH, content, (err) => {
+      if (err) reject(err);
+      else resolve();
+    });
+  });
+  await ssh.execCommand(`ls -t /opt/hytale/Server/config.json.backup.* 2>/dev/null | tail -n +6 | xargs rm -f 2>/dev/null || true`);
+  return true;
+}