- Add fast `test-timeout` guard chaining `test-timeout-lua`/`-shell`
- Wire `test-timeout` into `just ci` for harness regression coverage
- Consolidate fixtures into single `tests/harness/slow-case.lua`
- Tighten timeouts (libtest 2s / shell watchdog 3s) so each check is ~3s
- Update ADR-0009 and DEVELOPMENT.md for the new recipes and ci wiring