feat(alerts): 添加微信告警、WebSocket实时推送和地图功能

- 新增微信告警服务（wechat_service）和告警任务（alert_tasks）
- 新增 WebSocket 实时推送端点
- 新增监控管理模块（monitor）
- 增强统计仪表板：趋势图、区域分布、光功率历史
- 设备管理：添加坐标信息、标签系统、复合索引优化
- 前端：重构Dashboard/Charts页面，新增业务组件
- 新增5个数据库迁移（坐标、复合索引、标签、光功率历史、显示名）
- 更新部署配置和脚本
- 新增测试框架基础结构

backend/app/services/check_service.py

@@ -1,4 +1,5 @@
 """设备状态检查服务"""
+import time
 from typing import List, Dict, Optional
 from sqlalchemy.orm import Session
 from app.services.ssh_service import SSHService
@@ -6,6 +7,26 @@ from app.models.device import OLTDevice, ONUDevice, DeviceStatusHistory, Duplica
 from datetime import datetime
 import re
 
+# SSH 连接池缓存，TTL 5 分钟
+_conn_pool: Dict[int, tuple[SSHService, float]] = {}
+_POOL_TTL = 300
+
+def _get_cached_ssh(olt_ip: str, olt_user: str, olt_pass: str, olt_id: int) -> SSHService:
+    """获取缓存的 SSH 连接，过期自动重连"""
+    entry = _conn_pool.get(olt_id)
+    if entry:
+        ssh, ts = entry
+        if time.time() - ts < _POOL_TTL:
+            return ssh
+        try:
+            ssh.close()
+        except Exception:
+            pass
+    ssh = SSHService(olt_ip, olt_user, olt_pass)
+    ssh.connect()
+    _conn_pool[olt_id] = (ssh, time.time())
+    return ssh
+
 
 def parse_distance(distance_str: Optional[str]) -> Optional[int]:
     """将距离字符串转为整数，如 '<1000' -> 1000, '1234' -> 1234"""
@@ -29,9 +50,8 @@ class CheckService:
         if not olt:
             raise Exception(f"OLT 设备不存在: {olt_id}")
 
-        ssh = SSHService(olt.ip_address, olt.username, olt.password)
+        ssh = _get_cached_ssh(olt.ip_address, olt.username, olt.password, olt_id)
         try:
-            ssh.connect()
             output = ssh.execute_command(olt.slot_command)
             onu_info_dict, _ = ssh.parse_onu_info(output)
 
@@ -160,9 +180,8 @@ class CheckService:
         if not olt:
             raise Exception(f"OLT 设备不存在: {olt_id}")
 
-        ssh = SSHService(olt.ip_address, olt.username, olt.password)
+        ssh = _get_cached_ssh(olt.ip_address, olt.username, olt.password, olt_id)
         try:
-            ssh.connect()
             output = ssh.execute_command(olt.slot_command)
             onu_info_dict, duplicate_dict = ssh.parse_onu_info(output)
 
@@ -241,9 +260,8 @@ class CheckService:
         if not olt:
             raise Exception(f"OLT 设备不存在: {olt_id}")
 
-        ssh = SSHService(olt.ip_address, olt.username, olt.password)
+        ssh = _get_cached_ssh(olt.ip_address, olt.username, olt.password, olt_id)
         try:
-            ssh.connect()
             output = ssh.execute_command(olt.slot_command)
             onu_info_dict, duplicate_dict = ssh.parse_onu_info(output)