feat: 三项联动 — 计划过期提醒 + 拜访自动关闭 + 批量制定

1. 计划过期自动提醒:
   - scheduler.py 新增 check_overdue_plans()
   - 每日 9:00 检查过期计划(plan_date < today, status=计划中)
   - 按经理汇总 → 企微推送提醒消息

2. 拜访后自动关闭计划:
   - create_visit 后自动将匹配的计划标记为「已完成」
   - 条件: customer_id 匹配 + status=计划中 + plan_date <= visit_date

3. 亮灯表批量制定:
   - 红灯/黄灯卡片右上角 ☐ 复选框
   - 勾选后出现「批量制定计划」按钮
   - 弹窗统一设置日期+内容 → 批量 POST

Co-Authored-By: Claude <noreply@anthropic.com>

backend/app/api/visits.py

@@ -151,6 +151,19 @@ async def create_visit(
         customer.last_visit_manager_id = uuid.UUID(current_user["user_id"])
         db.add(customer)
 
+    # Auto-complete matching work plans for this customer
+    from app.models.work_plan import WorkPlan
+    plans_result = await db.execute(
+        select(WorkPlan).where(
+            WorkPlan.customer_id == data.customer_id,
+            WorkPlan.status == "计划中",
+            WorkPlan.plan_date <= parse_date(data.visit_date),
+        )
+    )
+    for plan in plans_result.scalars().all():
+        plan.status = "已完成"
+        append_entry(plan, current_user["name"], [{"field": "status", "from": "计划中", "to": "已完成", "reason": "拜访自动完成"}])
+
     # Create draft copies for companions
     for companion_id in data.companions:
         if companion_id != uuid.UUID(current_user["user_id"]):