feat: 消除同访草案机制，改为查询时通过 companions 数组覆盖

- 删除 POST /visits 中的草案创建逻辑（不再创建空拜访记录）
- 周报查询：manager 角色也显示同访的拜访记录
- 亮灯表覆盖：同访人也算客户拜访覆盖（UNION companions）
- 填报进度：同访人也算今日已填报
- 清理已有 2 条空草案记录

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

backend/app/services/light_board.py

@@ -85,19 +85,34 @@ async def get_light_board(
         for m in visible_managers
     }
 
-    # ── All customers with their last visit per manager ──
-    # Subquery: latest visit date + method per (manager_id, customer_id)
+    # ── All customers with their last visit per manager (including companions) ──
+    # UNION direct + companions (unnested), then DISTINCT ON to get the latest per (manager, customer)
+    from sqlalchemy import union_all, distinct
+    direct = select(
+        Visit.manager_id, Visit.customer_id, Visit.visit_date, Visit.visit_method,
+    )
+    companion = select(
+        func.unnest(Visit.companions).label("manager_id"),
+        Visit.customer_id,
+        Visit.visit_date,
+        Visit.visit_method,
+    ).where(Visit.companions.isnot(None))
+    combined = union_all(direct, companion).subquery()
+
+    # Get latest visit (date + method) per (manager_id, customer_id) using DISTINCT ON
     latest_visit = (
         select(
-            Visit.manager_id,
-            Visit.customer_id,
-            func.max(Visit.visit_date).label("last_visit_date"),
+            combined.c.manager_id,
+            combined.c.customer_id,
+            combined.c.visit_date.label("last_visit_date"),
+            combined.c.visit_method,
         )
-        .group_by(Visit.manager_id, Visit.customer_id)
+        .distinct(combined.c.manager_id, combined.c.customer_id)
+        .order_by(combined.c.manager_id, combined.c.customer_id, combined.c.visit_date.desc())
         .subquery()
     )
 
-    # Join: assignments → customers → latest_visit → visits (for method)
+    # Join: assignments → customers → latest_visit
     rows = await db.execute(
         select(
             CustomerAssignment.manager_id,
@@ -108,18 +123,13 @@ async def get_light_board(
             Customer.in_use_services,
             Customer.monthly_fee,
             latest_visit.c.last_visit_date,
-            Visit.visit_method,
+            latest_visit.c.visit_method,
         )
         .join(Customer, Customer.id == CustomerAssignment.customer_id)
         .outerjoin(latest_visit, and_(
             latest_visit.c.manager_id == CustomerAssignment.manager_id,
             latest_visit.c.customer_id == CustomerAssignment.customer_id,
         ))
-        .outerjoin(Visit, and_(
-            Visit.manager_id == CustomerAssignment.manager_id,
-            Visit.customer_id == CustomerAssignment.customer_id,
-            Visit.visit_date == latest_visit.c.last_visit_date,
-        ))
         .where(CustomerAssignment.role == "primary")
         .order_by(Customer.name)
     )