fix(correctness): 并发/事务/实体/时区/状态一致性修复

由 OCR（open-codereview.ai，deepseek-v4-flash）审查驱动修复：
- wallets 原子扣款防 double-spend；refund 条件更新幂等；findTransactions 分页
- financial/imports/occupancies/attendance 事务与 advisory lock；重复生成/提交幂等
- 矛盾校验器、日期区间、实体双映射/DECIMAL/nullable、时区统一（china-time）
- rbac-seed 防重激活、exam 权限恢复、状态一致性、路由顺序、N+1/IN 分块等性能项

Reviewed-by: OCR (open-codereview.ai)

apps/server/src/occupancies/occupancy-operations.service.ts

@@ -75,7 +75,14 @@ export class OccupancyOperationsService {
       await manager.save(occ);
       if (occ.bedId) await manager.update(Bed, occ.bedId, { status: 'available' });
       if (occ.lockerId) await manager.update(Locker, occ.lockerId, { status: 'available' });
-      await manager.update(Room, occ.roomId, { status: 'available' });
+      // 多床位房间不能因为单条退宿就置为 available：
+      // 只有该房间不再有任何在住记录时才更新房间状态。
+      const remainingActive = await manager.count(Occupancy, {
+        where: { roomId: occ.roomId, checkOutDate: IsNull() },
+      });
+      if (remainingActive === 0) {
+        await manager.update(Room, occ.roomId, { status: 'available' });
+      }
       return occ;
     });
   }
@@ -113,7 +120,14 @@ export class OccupancyOperationsService {
       if (oldOcc.lockerId) {
         await runner.manager.update(Locker, oldOcc.lockerId, { status: 'available' });
       }
-      await runner.manager.update(Room, oldOcc.roomId, { status: 'available' });
+      // 多床位房间不能因为单次换房就置为 available：
+      // 只有原房间不再有任何在住记录时才更新房间状态。
+      const oldRoomRemaining = await runner.manager.count(Occupancy, {
+        where: { roomId: oldOcc.roomId, checkOutDate: IsNull() },
+      });
+      if (oldRoomRemaining === 0) {
+        await runner.manager.update(Room, oldOcc.roomId, { status: 'available' });
+      }
       // 检查新房容量
       const newRoom = await withPessimisticWriteLock(
         runner.manager
@@ -365,12 +379,18 @@ export class OccupancyOperationsService {
         occ.billingEndDate = dto.billingEndDate || dto.checkOutDate;
         occ.checkOutReason = dto.checkOutReason || '';
         await runner.manager.save(occ);
-        // 更新房间状态
-        await runner.manager.update(Room, occ.roomId, { status: 'available' });
         // 释放床位/柜子
         if (occ.bedId) await runner.manager.update(Bed, occ.bedId, { status: 'available' });
         if (occ.lockerId)
           await runner.manager.update(Locker, occ.lockerId, { status: 'available' });
+        // 多床位房间不能因为单条退宿就置为 available：
+        // 只有该房间不再有任何在住记录时才更新房间状态。
+        const remainingActive = await runner.manager.count(Occupancy, {
+          where: { roomId: occ.roomId, checkOutDate: IsNull() },
+        });
+        if (remainingActive === 0) {
+          await runner.manager.update(Room, occ.roomId, { status: 'available' });
+        }
         success++;
       }
       await runner.commitTransaction();