Use multiple removal strategies for stubborn directories
Even after killing processes, rm -rf was still failing with 'Directory
not empty' errors on node_modules/.pnpm/parse-latin@4.3.0.
Enhanced removal with fallback strategies:
1. Standard rm -rf (fastest)
2. find -delete (files first, then directories - more thorough)
3. chmod -R 777 + rm -rf (handles permission issues)
4. Move to /tmp (ultimate fallback - lets OS clean up later)
Each strategy falls through to the next if it fails. The moving to /tmp
approach ensures the directory is at least out of the way even if we
can't delete it immediately, preventing the checkout action from
failing.
