v0.5.17 — setup capture reads step block, not headers

Fixed

• skills/manual-test/scripts/checklist_lib/setup.py — _do_http read the capture: map off h (the headers dict) instead of sb (the setup step block), so any capture: declared on a setup HTTP step silently resolved nothing — captured vars were never set. Read the map off sb.

No behavior change for setup steps without capture:.

Full changelog: see CHANGELOG.md