chore(contractiles): add bust/ + relocate k9 to svc/ (#27)

Applies estate-wide contractile layout fixes:
- Adds .machine_readable/contractiles/bust/ (Bustfile.a2ml + bust.ncl)
to complete the 6-verb set (intend/trust/must/bust/adjust/dust)
- Moves k9 out of .machine_readable/contractiles/ to
.machine_readable/svc/ per the k9-is-svc-not-contractile rule
(2026-04-18 convention)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath