created sh scirpt for uploasdin step files

uploadStepFiles.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+# save as push-step.sh and run in your repo folder
+git lfs track "*.step" "*.stp" 2>/dev/null || true
+git add .gitattributes *.step *.stp
+git commit -m "Update STEP models $(date +%F)"
+git push
+echo "STEP files pushed with LFS!"