Security review: 3 validated findings from ClawGuard scan

Hi, I ran a ClawGuard scan on this repo and manually validated a few concrete findings that look worth tightening:

1. `README.md:49`
- The quick-start docs advertise `curl | bash` as the setup path.
- Exact text: `One Command Setup: curl | bash and you're done`
- This normalizes remote-script execution without pinning or integrity verification.

2. `copaw/src/copaw_worker/sync.py:448`
- The sync cleanup path removes directories with `shutil.rmtree(child)`.
- In context this is deleting local skill directories based on remote state, which deserves extra path safety checks and guardrails before recursive delete.

3. `copaw/src/copaw_worker/worker.py:466`
- Another cleanup path removes directories with `shutil.rmtree(child)` when skills are considered stale.
- Same concern here: recursive delete on dynamically selected paths should be tightly constrained and validated.

I skipped several scanner hits that looked like likely false positives and only kept the ones above because they were easy to confirm directly.

If useful, I can share the full scan output in a follow-up.

Scanner: https://github.com/hesoyam2221/clawguard