The animateMove method existed on the board but was never called.
Game scene was still doing board.setPosition() instantly.

Fixed:
- Player moves: animateMove(from, to) → piece slides 200ms → then setPosition
- Bot moves: same — piece slides smoothly before board updates
- Initial position: stays instant (correct — no animation needed on load)

The animation method uses requestAnimationFrame to interpolate piece
position linearly from source square to destination over 200ms.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>