Completion note

The runtime-boundaries capability becomes a live spec with this archive. The refactor preserved existing gameplay, CommonJS and share data, snapshots, and public engine/stage/board entry points. Verification passed 183 Node tests, the production build, and desktop/mobile browser flows covering rules, Pause/Index/Workshop, Gift, Win/continue, automata WAIT, and Undo after death.

The browser loop found and fixed a missing extracted renderer import and a stale turn index after Undo. The architecture review at docs/architecture-review.md records the remaining work: geometry-driven pointer hit regions, further juice decomposition, shared pack/engine schema validation, a mechanics-aware snapshot/solver codec, and an explicit automata conflict policy. Gates, switches, and crumble tiles remain future behavior changes.