feat(receipt-import): add refresh categories endpoint and UI integration

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

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

@@ -12,6 +12,7 @@ import { FileInterceptor } from '@nestjs/platform-express';
 import { memoryStorage } from 'multer';
 import { ReceiptImportService } from './receipt-import.service';
 import { ParsedReceiptItem } from './dto/parsed-receipt-item.dto';
+import { AuthGuard } from '@nestjs/passport';
 
 const ALLOWED_MIMES = [
   'image/jpeg',
@@ -52,4 +53,11 @@ export class ReceiptImportController {
     const userId = typeof req?.user?.id === 'number' ? req.user.id : undefined;
     return this.receiptImportService.parseReceipt(file, isPremium, userId);
   }
+
+  @Post('refresh-categories')
+  @UseGuards(AuthGuard('jwt'))
+  async refreshCategories() {
+    await this.receiptImportService.loadCategories();
+    return { message: 'Kategorier har uppdaterats.' };
+  }
 }