Add reaction lexicon for move comments
- Create boo.sky.go.reaction lexicon with move, emoji, text, stars fields
- Add ReactionRecord type to types.ts
- Add fetchMoveReactions and fetchGameReactions to atproto-client
- Create /api/games/[id]/reaction POST endpoint for creating reactions
- Add reactions panel to game page showing comments on selected move
- Display emoji badges on moves with reactions in move history
- Add reaction form with emoji, star rating, and text input
- Style reactions panel and form components
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>