feat: enable file upload support for announcement creation with multipart form data handling.

Backend/src/controllers/announcementsController.ts

@@ -1,4 +1,4 @@
-import { Body, Delete, Get, Path, Post, Put, Query, Request, Response, Route, Security, SuccessResponse, Tags, UploadedFile } from 'tsoa';
+import { Body, Delete, Get, Path, Post, Put, Query, Request, Response, Route, Security, SuccessResponse, Tags, UploadedFile, UploadedFiles, FormField } from 'tsoa';
 import { ValidationError } from '../middleware/errorHandler';
 import { AnnouncementsService } from '../services/announcements.service';
 import {
@@ -47,8 +47,8 @@ export class AnnouncementsController {
     }
 
     /**
-     * สร้างประกาศใหม่
-     * Create a new announcement
+     * สร้างประกาศใหม่ (พร้อมไฟล์แนบ)
+     * Create a new announcement with optional file attachments
      * @param courseId - รหัสคอร์ส / Course ID
      */
     @Post()
@@ -59,17 +59,23 @@ export class AnnouncementsController {
     public async createAnnouncement(
         @Request() request: any,
         @Path() courseId: number,
-        @Body() body: CreateAnnouncementBody
+        @FormField() data: string,
+        @UploadedFiles() files?: Express.Multer.File[]
     ): Promise<CreateAnnouncementResponse> {
         const token = request.headers.authorization?.replace('Bearer ', '');
         if (!token) throw new ValidationError('No token provided');
+
+        // Parse JSON data field
+        const parsed = JSON.parse(data) as CreateAnnouncementBody;
+
         return await announcementsService.createAnnouncement({
             token,
             course_id: courseId,
-            title: body.title,
-            content: body.content,
-            status: body.status,
-            is_pinned: body.is_pinned,
+            title: parsed.title,
+            content: parsed.content,
+            status: parsed.status,
+            is_pinned: parsed.is_pinned,
+            files,
         });
     }