docs: implementation plan for inferred GC + mark-sweep (iteration 7b)
Phased plan argued from the 2026-08-11 spec: Phase 1 additive inference +
--dump-gc (golden-neutral), Phase 2 demand promotion + rewire field kinds to
the inferred set (+ @gc-in-source error), Phase 3 the runtime collector swap
(header rewrite, traced list, tri-color mark + Yuasa barrier, retire RC, .wob
bump), Phase 4 doc migration. Each phase has file targets + verify commands.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
shoney.arickathil
4737477b23