2026-07-13 (itd-85 M3): three-tier-layout does NOT require .abcd/.work.local/ to

2026-07-13 (itd-85 M3): three-tier-layout does NOT require .abcd/.work.local/ to be present (diverges from the plan's literal "present and gitignored") — it is created on demand and a fresh clone has none; requiring presence would flag every clean checkout. The load-bearing assertion is "if present, gitignored". Mechanics revision, premise intact.