The course's own engine as of the end of Module 9. Part I's card engine is unchanged, and all of its tests still pass. The Part II engine in src/engine/puzzle/ now plays a whole turn: movement, parse, conversion, parse, hazards, win, parse. Module 8's reference was the starting point, so a diff between the two shows what this module adds.

cards/ (at the package root; not in this directory): Part I's card data, a copy of course/cards/ staged by tools/verify-references.mjs. Part II doesn't read it.
src/engine/puzzle/: the Part II engine. It names no noun: the engine's own words are the operators IS, AND, NOT, the meta-noun TEXT, the property PUSH of the base rule TEXT IS PUSH, the property YOU, which picks the objects that move, and from Module 9 the properties WIN (the win check) and FLOAT (which objects share a tile).
- turn.ts (new): the turn. Phase, TURN (the phases in order) and Hazard (content's rule for what destroys what).
- level.ts: a level in play. Module 9 adds Level.step, which runs the phases of TURN; the conversion phase (X IS Y in place, X IS X locks, X IS NOT X deletes, and ... IS NOT Y keeps every object it names from becoming a Y, as hasProperty settles negation per object); the hazards phase, which runs content's hazards in order; the win check; Level.sharing (the other objects on a tile at the same float level); won and lost. The Level constructor takes the hazards. moveYou is now movement, then a reparse.
- grid.ts: Module 9 adds Board.setKind.
- word.ts: Module 9 adds Lexicon.thingNamed (what a conversion into a noun makes).
- movement.ts, parse.ts, resolve.ts: unchanged.
- index.ts: the module's exports.
The rest of src/engine/: Part I, unchanged.
src/content/hazards.ts (new) and src/content/index.ts: the hazards, in the order the engine runs them: SINK, HOT/MELT, DEFEAT. What destroys what at the end of a turn is content, not engine.
src/content/movement.ts: unchanged.
src/content/words.json: Module 9 adds HOT, MELT, SINK, DEFEAT and FLOAT, and ALL, the Module 7 Expansion Drop, which the Module 9 tests need.
src/harness.ts: the adapter the course tests call. Module 9 adds step, won and lost on Baba.

Run it with the module's tests: node tools/verify-references.mjs 09 from the course repository.