feat: enhance JWT authentication and quick import functionality with logging for better traceability

Co-authored-by: Copilot <copilot@github.com>

backend/src/quick-import/quick-import.controller.ts

@@ -15,6 +15,19 @@ export class QuickImportController {
     FileInterceptor('file', {
       storage: memoryStorage(),
       limits: { fileSize: 10 * 1024 * 1024 },
+      fileFilter: (req, file, callback) => {
+        if (
+          file.mimetype === 'application/pdf' ||
+          file.mimetype === 'application/octet-stream' ||
+          file.mimetype === 'image/jpeg' ||
+          file.mimetype === 'image/png' ||
+          file.mimetype === 'image/webp'
+        ) {
+          callback(null, true);
+        } else {
+          callback(new Error('Otillåten filtyp. Använd JPEG, PNG, WebP eller PDF.'), false);
+        }
+      },
     }),
   )
   async importFromInput(

backend/src/quick-import/quick-import.service.ts

@@ -76,6 +76,8 @@ export class QuickImportService {
    * Importerar från en uppladdad fil
    */
   async importFromUpload(file: Express.Multer.File): Promise<QuickImportResult | ReceiptImportResult> {
+    this.logger.log('MIME-typ:', file.mimetype);
+    this.logger.log('Token:', file.originalname);
     const kind = file.mimetype.startsWith('image/') ? 'image' : 'pdf';
     return this.importFromBuffer(file.buffer, kind);
   }