fix(network): auto-detect wired iface and ping via -I for hasInternet

- Scan sysfs for carrier when CLAWD_ETH_IFACE unset (end0/enp* etc.)
- Explicit CLAWD_ETH_IFACE still pins a single interface
- Ping fallback uses -I wired iface when default route fails (e.g. AP on wlan)
- Exclude can/docker/veth/wl* and similar from auto scan
- Clarify client log when waiting for WAN

Made-with: Cursor

lib/client.js

@@ -110,7 +110,7 @@ class ClawClient {
       this._connectionStarted = true;
       await this._proceedWithConnection();
     } else if (!hasInternet()) {
-      log.info('clawd', '等待网络就绪（WiFi 配网或网线接入）...');
+      log.info('clawd', '等待外网就绪（可配网；有线已接时将自动识别网卡，含非 eth0 口）...');
     }
   }