fix: 修复多个高优 Issue (#160, #165, #156, #159, #151)

- #160 Gateway 死循環: _autoPairAndReconnect 后不调用 reconnect() 避免重置计数器
- #165 readConfig 未定义: 替换为内联 fs.readFileSync/writeFileSync
- #156 systemd PATH: findOpenclawBin 添加 npm 全局路径, systemd 服务注入 PATH
- #159 Docker 双容器冲突: 新增 DISABLE_GATEWAY_SPAWN 环境变量开关
- #151 Gateway 检测冲突: linuxCheckGateway 验证进程名, 拒绝操作非 OpenClaw 进程

scripts/linux-deploy.sh

@@ -254,6 +254,7 @@ Restart=on-failure
 RestartSec=5
 Environment=NODE_ENV=production
 Environment=HOME=$HOME
+Environment=PATH=$HOME/.npm-global/bin:$HOME/.local/bin:$HOME/.volta/bin:$(dirname $(which node)):$PATH
 
 [Install]
 WantedBy=multi-user.target
@@ -275,6 +276,7 @@ Restart=on-failure
 RestartSec=5
 Environment=NODE_ENV=production
 Environment=HOME=$HOME
+Environment=PATH=$HOME/.npm-global/bin:$HOME/.local/bin:$HOME/.volta/bin:$(dirname $(which node)):$PATH
 
 [Install]
 WantedBy=default.target