Added Validation to API requests.

- Added Symfony Validation Lib.
- Updated API DTOs to include validation constraints.

src/Request/SearchPricesForCategoryRequest.php

@@ -2,16 +2,21 @@
 
 namespace App\Request;
 
+use DateTimeInterface;
 use OpenApi\Attributes as OA;
+use Symfony\Component\Validator\Constraints as Assert;
 
 class SearchPricesForCategoryRequest
 {
     #[OA\Property(description: 'Room category ID')]
+    #[Assert\NotBlank]
     public int $roomCategory;
 
     #[OA\Property(description: 'Period start date')]
-    public \DateTime $startDate;
+    #[Assert\NotBlank]
+    public DateTimeInterface $startDate;
 
     #[OA\Property(description: 'Period end date')]
-    public \DateTime $endDate;
+    #[Assert\NotBlank]
+    public DateTimeInterface $endDate;
 }