fix: 修复6个边缘侧问题 + 单元测试

1. 删除 ConfigAgent (与 MQTT 配置更新重叠且未启用)
2. OTA 完整安装流程: 解压tar.gz -> 校验ELF -> 替换二进制 -> systemctl重启
3. StreamManager stopAll 添加 Wait() 防止僵尸进程
4. InferClient socket 读写添加 timeout 防止永久阻塞
5. Heartbeat 集成 NPU 监控 (npu-smi + fallback 脚本)
6. 配置更新时动态重启 ffmpeg 以应用新 fps

systemd/edge-agent.service

@@ -8,7 +8,7 @@ Type=simple
 WorkingDirectory=/opt/tianyan-edge
 Environment="PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
 Environment="LD_LIBRARY_PATH=/usr/local/Ascend/ascend-toolkit/latest/arm64-linux/lib64:/usr/local/Ascend/driver/lib64"
-ExecStart=/opt/tianyan-edge/edge-agent -config /opt/tianyan-edge/config/edge.yaml
+ExecStart=/opt/tianyan-edge/bin/edge-agent -config /opt/tianyan-edge/config/edge.yaml
 Restart=on-failure
 RestartSec=5
 StartLimitBurst=5