Errors are not propagated via APIs properly

Please select the area the issue is related to

Area/Management (Management API or Management Portal UI)

Please select the aspect the issue is related to

Aspect/API (API backends, definitions, contracts, interfaces, OpenAPI)

Description

When errors are captured at downstream methods, they are ignored and new/generic errors are passed via the REST APIs making it hard to capture the orginal error.

Steps to Reproduce

1. Create an API without backends
2. Deploy it to a gateway

Error shown via the REST APIs:

{
    "code": 400,
    "message": "Bad Request",
    "description": "Invalid API deployment configuration"
}

Actual error:

// validateDeploymentRequest validates the deployment request
func (s *APIService) validateDeploymentRequest(req *dto.APIRevisionDeployment, apiId, orgId string) error {
	if req.GatewayID == "" {
		return errors.New("gateway Id is required")
	}
	if req.VHost == "" {
		return errors.New("vhost is required")
	}
	// TODO - vHost validation
	gateway, err := s.gatewayRepo.GetByUUID(req.GatewayID)
	if err != nil {
		return fmt.Errorf("failed to get gateway: %w", err)
	}
	if gateway == nil {
		return fmt.Errorf("failed to get gateway: %w", err)
	}
	if gateway.OrganizationID != orgId {
		return fmt.Errorf("failed to get gateway: %w", err)
	}

	// Validate that the API has at least one backend service attached
	backendServices, err := s.backendServiceRepo.GetBackendServicesByAPIID(apiId)
	if err != nil {
		return fmt.Errorf("failed to get backend services for API: %w", err)
	}
	if len(backendServices) == 0 {              <<<<<<<<<<<<<<<<<
		return errors.New("API must have at least one backend service attached before deployment")
	}

Severity Level of the Issue

Severity/Major (Important functionality is broken. Should be prioritized. Doesn't need immediate attention)

Environment Details (with versions)

No response

The reported path is APIService.validateDeploymentRequest, including gatewayRepo.GetByUUID and backendServiceRepo.GetBackendServicesByAPIID; start there and trace how returned errors become REST responses. Review the existing API error-response handling, then verify that downstream validation errors reach the API response with their useful message instead of a generic deployment error.