Prevent PureLock Go cache restore collisions (#57948)

* Initial plan

* Avoid Go cache restore in PureLock agent

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

* Merge main into purelock cache fix

Co-authored-by: gh-aw-bot <259018956+gh-aw-bot@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>
Co-authored-by: gh-aw-bot <259018956+gh-aw-bot@users.noreply.github.com>

Author: 3 people

.github/workflows/purelock.lock.yml

@@ -139,7 +139,9 @@ steps:
     uses: actions/setup-go@v7.0.0
     with:
       go-version-file: go.mod
-      cache: true
+      # The sandbox mounts the runner's Go module cache, so restoring it again
+      # causes setup-go's tar extraction to fail on existing files.
+      cache: false
   - name: Download PureLock bundle
     uses: actions/download-artifact@v8.0.1
     with: