Refactor Tender Handler to Use ListTendersRequest Struct

- Updated the GetPublicTenders handler to utilize a new ListTendersRequest struct for improved clarity and organization of parameters.
- Changed the handling of `publication_from` and `publication_to` query parameters to use pointers for optional timestamp values.
- Enhanced the service call to ListTenders, aligning with the new request structure and improving the overall code maintainability.

internal/tender/handler.go

@@ -272,21 +272,29 @@ func (h *TenderHandler) GetPublicTenders(c echo.Context) error {
 		companyID = &customerCompanyID
 	}
 
-	from := int64(0)
+	var from *int64
 	if fromParam := c.QueryParam("publication_from"); fromParam != "" {
 		if parsed, err := strconv.ParseInt(fromParam, 10, 64); err == nil {
-			from = parsed
+			from = &parsed
 		}
 	}
 
-	to := int64(0)
+	var to *int64
 	if toParam := c.QueryParam("publication_to"); toParam != "" {
 		if parsed, err := strconv.ParseInt(toParam, 10, 64); err == nil {
-			to = parsed
+			to = &parsed
 		}
 	}
 
-	result, err := h.service.RecommendTenders(c.Request().Context(), companyID, &from, &to, limit, offset)
+	req := ListTendersRequest{
+		Criteria:  criteria,
+		Limit:     limit,
+		Offset:    offset,
+		CompanyID: companyID,
+		From:      from,
+		To:        to,
+	}
+	result, err := h.service.ListTenders(c.Request().Context(), req)
 	if err != nil {
 		return response.InternalServerError(c, "Failed to retrieve tenders")
 	}