fix: normalize negative offset to zero in media filter

internal/handlers/media.go

@@ -659,6 +659,10 @@ func (mh *MediaHandler) ListMediaItemsFiltered(c echo.Context) error {
 		limit = 50
 	}
 
+	if offset < 0 {
+		offset = 0
+	}
+
 	if sort == "" {
 		sort = "created_at DESC"
 	}