The client half of the canon log contract: typed RefCounted model with
invariants-in-the-model, Luck-centric game state, new-game construction
from origin+world+creation, turn-to-turn mutators, and a pure regex tag
extractor. Headless GUT-tested logic layer; UI/HTTP/save-load deferred.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
