src/test/hookHarness.ts gives the tests that call hooks and components as
plain functions one fake React with React's semantics: state initialized
once with stable setters, the reducer applied with a dispatch spy, refs kept,
memos and callbacks recomputed only on a changed dependency, effects run by
commit() only when a dependency changed (cleanups first), and every hook it
does not cover throws instead of reaching the real React. Each semantic is
proved by hookHarness.test.ts, which also checks that the module imports
React only as a type.
Refs #409
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
