feat: edc-web 设备日志管理页 + 在线状态实时刷新

- 新增 /device-logs 设备事件日志管理页 (admin 权限)
  - 支持按设备序列号/事件类型筛选查询
  - 支持 admin 按条件删除日志
  - 不同事件类型彩色标识 (在线=绿, 离线=红, 通信不良=橙)
- 新增 /api/devices/<id>/status 设备状态 API
- 设备列表页：每 5s 异步刷新所有设备在线状态
- 测试操作页：顶部显示设备状态，每 5s 异步刷新
- dnt_info state 支持三态显示 (在线/离线/通信不良)
- 导航栏增加「设备日志」入口 (admin only)

edc-web/app/models.py

@@ -827,3 +827,79 @@ def delete_test_data(serial: str = "", date_from: str = "",
         return cnt
     finally:
         conn.close()
+
+
+# ─── tb_device_log ─────────────────────────────────────────────────
+
+def get_device_logs(page: int = 1, per_page: int = 30,
+                    serial: str = "", event_type: str = "") -> tuple[list[dict], int]:
+    """分页查询设备事件日志，返回 (records, total)"""
+    conn = get_conn()
+    try:
+        with conn.cursor() as cur:
+            where = []
+            params = []
+            if serial:
+                where.append("device_serial LIKE %s")
+                params.append(f"%{serial}%")
+            if event_type:
+                where.append("event_type = %s")
+                params.append(event_type)
+
+            where_clause = " AND ".join(where) if where else "1=1"
+
+            cur.execute(
+                f"SELECT COUNT(*) as total FROM tb_device_log WHERE {where_clause}",
+                params,
+            )
+            total = cur.fetchone()["total"]
+
+            offset = (page - 1) * per_page
+            cur.execute(
+                f"SELECT * FROM tb_device_log WHERE {where_clause} "
+                f"ORDER BY id DESC LIMIT %s OFFSET %s",
+                params + [per_page, offset],
+            )
+            return cur.fetchall(), total
+    finally:
+        conn.close()
+
+
+def delete_device_logs(serial: str = "", event_type: str = "",
+                       date_from: str = "", date_to: str = "") -> int:
+    """删除符合条件的设备日志，返回删除行数。至少需要一个条件。"""
+    conn = get_conn()
+    try:
+        with conn.cursor() as cur:
+            where = []
+            params = []
+            if serial:
+                where.append("device_serial LIKE %s")
+                params.append(f"%{serial}%")
+            if event_type:
+                where.append("event_type = %s")
+                params.append(event_type)
+            if date_from:
+                where.append("create_time >= %s")
+                params.append(date_from if len(date_from) > 10 else date_from)
+            if date_to:
+                where.append("create_time <= %s")
+                params.append(date_to if len(date_to) > 10 else date_to + " 23:59:59")
+
+            if not where:
+                return 0
+
+            where_clause = " AND ".join(where)
+            cur.execute(
+                f"SELECT COUNT(*) as cnt FROM tb_device_log WHERE {where_clause}",
+                params,
+            )
+            cnt = cur.fetchone()["cnt"]
+
+            cur.execute(
+                f"DELETE FROM tb_device_log WHERE {where_clause}", params,
+            )
+        conn.commit()
+        return cnt
+    finally:
+        conn.close()