feat: add Student-User association and activate all notification TODOs

apps/server/src/occupancies/occupancies.controller.ts

@@ -13,6 +13,9 @@ import {
   UseInterceptors,
   UploadedFile,
 } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import { Repository } from 'typeorm';
+import { Student } from '../entities/student.entity';
 import { FileInterceptor } from '@nestjs/platform-express';
 import type { Response } from 'express';
 import { OccupanciesService } from './occupancies.service';
@@ -32,6 +35,7 @@ export class OccupanciesController {
     private service: OccupanciesService,
     private logService: OperationLogsService,
     private readonly notificationsService: NotificationsService,
+    @InjectRepository(Student) private studentRepo: Repository<Student>,
   ) {}
 
   @Get()
@@ -81,7 +85,18 @@ export class OccupanciesController {
       ipAddress,
       userAgent,
     });
-    // TODO: Send notification for check_in — studentId→userId mapping unavailable
+    // Send check_in notification
+    try {
+      const student = await this.studentRepo.findOne({ where: { id: dto.studentId } });
+      if (student?.userId) {
+        void this.notificationsService.create({
+          recipientIds: [student.userId],
+          type: NotificationType.CHECK_IN,
+          title: '入住通知',
+          content: `您已入住房间 #${dto.roomId}`,
+        });
+      }
+    } catch (_) { /* don't block response */ }
     return result;
   }
 
@@ -100,7 +115,18 @@ export class OccupanciesController {
       ipAddress,
       userAgent,
     });
-    // TODO: Send notification for check_out — studentId→userId mapping unavailable
+    // Send check_out notification
+    try {
+      const student = await this.studentRepo.findOne({ where: { id: result.studentId } });
+      if (student?.userId) {
+        void this.notificationsService.create({
+          recipientIds: [student.userId],
+          type: NotificationType.CHECK_OUT,
+          title: '退宿通知',
+          content: `您已退宿房间 #${result.roomId}`,
+        });
+      }
+    } catch (_) { /* don't block response */ }
     return result;
   }