Layout engine:
- Non-doubles are landscape (w=48, h=24) in horizontal chains
- Doubles are portrait (w=24, h=48) perpendicular to horizontal chains
- Tiles positioned touching each other with GAP=3px between
- Properly computes half-extents for advance distance
- Endpoints positioned beyond last tile in chain direction

Tile renderer:
- Uses w>h to detect landscape orientation (no rotation param needed)
- Left/right pips in landscape, top/bottom pips in portrait
- Doubles get accent background

Board:
- Ghost and animate tiles compute orientation from layout dirIdx
- No rotation applied (dimensions are pre-computed correctly)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>