Per Codex's Phase 2 audit notes. Moved the drag-snap (lineFrom) and find-match
(matchWord) logic into $lib/wordsearch.js and added vitest coverage:
- lineFrom always yields a straight, in-bounds path — a non-straight drag snaps,
never returns bent; single cell and edge-clamping covered.
- matchWord matches forward + reversed selections, is a harmless no-op on an
already-found word (so completion/best-time can't double-record), and returns
null for non-words / too-short selections.
Restore behaviour audited: finish() (which records best-time) only runs when the
final word is found mid-play; on refresh, restore() repopulates found cells +
time and the derived status flips to done WITHOUT calling finish(), so best-time
never re-records. First JS test runner for the frontend (npm test → vitest run).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
