feat: edc-web 支持车检器序列号输入与显示

- 自动化测试区域新增「车检器序列号」输入框
- 回车键自动触发「开始」按钮
- /api/automation/start 接收 detector_serial，写入 tb_pending_detector
- 测试操作页 + 测试信息页（全部/B2/B4）显示序列号，空时显示 '-'
- 页面加载和测试结束后焦点自动回到序列号输入框（全选），方便连续测试

edc-web/app/models.py

@@ -942,3 +942,21 @@ def delete_device_logs(serial: str = "", event_type: str = "",
         return cnt
     finally:
         conn.close()
+
+
+# ─── tb_pending_detector ───────────────────────────────────────────
+
+def set_pending_detector_serial(dnt_id: int, detector_serial: str):
+    """设置待插入的车检器序列号（UPSERT）"""
+    conn = get_conn()
+    try:
+        with conn.cursor() as cur:
+            cur.execute(
+                """INSERT INTO tb_pending_detector (dnt_id, detector_serial)
+                   VALUES (%s, %s)
+                   ON DUPLICATE KEY UPDATE detector_serial = VALUES(detector_serial)""",
+                (dnt_id, detector_serial),
+            )
+        conn.commit()
+    finally:
+        conn.close()