First Part II module. The cumulative reference adds a second engine
(src/engine/puzzle: grid, lexer, parser) beside Part I's; nouns and
properties are data in src/content/words.json, and the engine names only
IS/AND/NOT/TEXT and the base rule TEXT IS PUSH. Rules are recompiled from
the board on every change; rules() is a sorted set. Adds the M6 scenarios
and tests (rows, columns, shared IS, AND distribution, stacked text, base
rule), the HOT word as a data-only Expansion Drop, the lesson with the
Part II bridge, and the Rust LevelDef shape in harness.md.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
