- Add 'sisyphus: working' label when Sisyphus starts working on an issue/PR
- Remove label when work completes (success or failure)
- Label operations use gh CLI with idempotent commands
- Handles both issues and PRs with proper conditional logic
- Uses || true for error handling to prevent workflow failures
Closes#202
Co-authored-by: sisyphus-dev-ai <sisyphus-dev-ai@users.noreply.github.com>