fix: parse multipart uploads for shop-chat files and chat-room images

Same root cause as the shop logo fix: these two routes still expected
req.files.<field> (the removed express-form-data pattern) with no
multer middleware in front of them, so:
- POST /shop-chat/:shopId/messages/file always rejected with "فایل
  الزامی است" even when a valid image/video was sent.
- POST /chat-rooms room creation silently dropped room_image, and
  would lose all text fields (title, visibility, ...) whenever the
  request was multipart (i.e. whenever an image was attached).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

controllers/application/chatRooms/chatRoomController.js

@@ -225,14 +225,14 @@ const createRoom = async (req, res, next) => {
     }
 
     let imagePath = null
-    const imageFile = req.files?.room_image
+    const imageFile = req.file
     if (imageFile) {
       const uploadDir = path.join(__dirname, '../../../storage/chat-rooms')
       if (!fs.existsSync(uploadDir)) {
         fs.mkdirSync(uploadDir, { recursive: true })
       }
-      // اسمِ فایل هیچ‌وقت مستقیم از ورودیِ کاربر (imageFile.name) گرفته نمی‌شه — فقط پسوندش
-      const uniqueFileName = `${Date.now()}-${crypto.randomUUID()}${path.extname(imageFile.name || '')}`
+      // اسمِ فایل هیچ‌وقت مستقیم از ورودیِ کاربر (imageFile.originalname) گرفته نمی‌شه — فقط پسوندش
+      const uniqueFileName = `${Date.now()}-${crypto.randomUUID()}${path.extname(imageFile.originalname || '')}`
       const filePath = path.join(uploadDir, uniqueFileName)
       await fs.move(imageFile.path, filePath)
       await optimizeImageFile(filePath, { maxDimension: 800 })