Fix checkout ENOTEMPTY error with pre-checkout cleanup
The previous approach of using clean: false caused the checkout action
to fail when trying to delete non-empty directories (ENOTEMPTY error).
This change:
- Adds a pre-checkout cleanup step that forcefully removes node_modules
and .git directories before checkout runs
- Removes clean: false to let checkout use its default behavior
- Uses continue-on-error to ensure the job continues even if cleanup
has issues
This prevents the ENOTEMPTY errors while still cleaning up artifacts.
