feat: add structured logging, process watchdog, and systemd hardening

- Add lib/logger.js: timestamped structured logging with 5MB x 5 file rotation
- Add lib/watchdog.js: generic child process supervisor with rate-limited restarts
- Enhance client.js: WS ping/pong liveness detection, uncaughtException/unhandledRejection handlers, systemd sd-notify integration
- Refactor frpc.js: FrpcManager now delegates to Watchdog instead of manual spawn/exit
- Enhance install.sh: environment file, log directory, systemd resource limits, security hardening, WatchdogSec=60
- Replace all console.log/warn/error with structured logger across modules

Made-with: Cursor

bin/clawd.js

@@ -2,10 +2,20 @@
 'use strict';
 
 const { ClawClient } = require('../lib/client');
+const log = require('../lib/logger');
 
 const client = new ClawClient();
 client.start();
 
-// 优雅退出
-process.on('SIGINT',  () => { client.stop(); process.exit(0); });
-process.on('SIGTERM', () => { client.stop(); process.exit(0); });
+let stopping = false;
+
+function shutdown(signal) {
+  if (stopping) return;
+  stopping = true;
+  log.info('clawd', `收到 ${signal}，正在停止...`);
+  client.stop();
+  setTimeout(() => process.exit(0), 500);
+}
+
+process.on('SIGINT',  () => shutdown('SIGINT'));
+process.on('SIGTERM', () => shutdown('SIGTERM'));