Improve error handling for tender retrieval by adding specific checks for "tender not found" in handler and service layers.

internal/tender/handler.go

@@ -447,6 +447,9 @@ func (h *TenderHandler) GetDocuments(c echo.Context) error {
 		if errors.Is(err, orm.ErrDocumentNotFound) {
 			return response.NotFound(c, "Tender not found")
 		}
+		if err.Error() == "tender not found" {
+			return response.NotFound(c, "Tender not found")
+		}
 		return response.InternalServerError(c, "Failed to retrieve tender documents")
 	}
 
@@ -478,6 +481,9 @@ func (h *TenderHandler) DownloadDocuments(c echo.Context) error {
 
 	download, err := h.service.DownloadDocuments(c.Request().Context(), id)
 	if err != nil {
+		if err.Error() == "tender not found" {
+			return response.NotFound(c, "Tender not found")
+		}
 		if errors.Is(err, ErrTenderDocumentNotFound) {
 			return response.NotFound(c, "Tender documents not found")
 		}
@@ -502,6 +508,9 @@ func (h *TenderHandler) DownloadDocuments(c echo.Context) error {
 func (h *TenderHandler) streamDocumentDownload(c echo.Context, tenderID, filename string) error {
 	download, err := h.service.DownloadDocument(c.Request().Context(), tenderID, filename)
 	if err != nil {
+		if err.Error() == "tender not found" {
+			return response.NotFound(c, "Tender not found")
+		}
 		if errors.Is(err, ErrTenderDocumentNotFound) {
 			return response.NotFound(c, "Tender document not found")
 		}

internal/tender/service.go

@@ -498,6 +498,9 @@ func (s *tenderService) GetDocuments(ctx context.Context, id string) (*TenderDoc
 		})
 		return nil, fmt.Errorf("failed to get tender: %w", err)
 	}
+	if tender == nil {
+		return nil, fmt.Errorf("tender not found")
+	}
 
 	empty := func() *TenderDocumentsResponse {
 		return &TenderDocumentsResponse{
@@ -1082,6 +1085,9 @@ func (s *tenderService) GetAISummary(ctx context.Context, id string) (*AISummary
 		})
 		return nil, fmt.Errorf("failed to get tender: %w", err)
 	}
+	if t == nil {
+		return nil, fmt.Errorf("tender not found")
+	}
 
 	noticeID := strings.TrimSpace(t.NoticePublicationID)
 	emptyResp := func(source string) *AISummaryResponse {