new endpoint to return product list

app/utils/responseErrors/responseErrors.go

@@ -43,6 +43,9 @@ var (
 	ErrInvalidXHTML   = errors.New("text is not in xhtml format")
 	ErrAIResponseFail = errors.New("AI responded with failure")
 	ErrAIBadOutput    = errors.New("AI response does not obey the format")
+
+	// Typed errors for product list handler
+	ErrBadPaging = errors.New("bad or missing paging attribute value in header")
 )
 
 // Error represents an error with HTTP status code
@@ -123,6 +126,9 @@ func GetErrorCode(c fiber.Ctx, err error) string {
 	case errors.Is(err, ErrAIBadOutput):
 		return i18n.T_(c, "error.err_ai_bad_output")
 
+	case errors.Is(err, ErrBadPaging):
+		return i18n.T_(c, "error.err_bad_paging")
+
 	default:
 		return i18n.T_(c, "error.err_internal_server_error")
 	}
@@ -154,7 +160,8 @@ func GetErrorStatus(err error) int {
 		errors.Is(err, ErrInvalidPassword),
 		errors.Is(err, ErrBadAttribute),
 		errors.Is(err, ErrBadField),
-		errors.Is(err, ErrInvalidXHTML):
+		errors.Is(err, ErrInvalidXHTML),
+		errors.Is(err, ErrBadPaging):
 		return fiber.StatusBadRequest
 	case errors.Is(err, ErrEmailExists):
 		return fiber.StatusConflict