fix(login): 修复人脸识别登录界面返回时串口连接超时问题

- 每次回到识别界面时重新打开串口连接
- 防止PLC SDK内部连接超时导致出盘失败
- 添加串口开启成功和失败的日志记录

app/src/main/java/com/sw/platecabinet/activity/LoginByFaceActivity.kt

@@ -734,6 +734,15 @@ class LoginByFaceActivity : BaseActivity<ActivityLoginFaceBinding>(),
                 goInitActivity()
                 return
             }
+            // 每次回到识别界面时重新打开串口，防止 PLC SDK 内部连接超时导致出盘失败
+            PlcHelper.getInstance(this).openSerialPort(object : PlcCallback<String> {
+                override fun onSuccess(result: String) {
+                    loadLogInfo("onResume openSerialPort 成功: $result")
+                }
+                override fun onError(message: String) {
+                    loadLogInfo("onResume openSerialPort 失败: $message")
+                }
+            })
             lifecycleScope.launch {
                 try {
                     val faceDao = FaceDatabase.getInstance(this@LoginByFaceActivity).faceDao()