Replace tenuki mini boards with server-rendered SVGs
- Created shared board-svg.ts utility for generating board SVGs
- Added /api/games/[id]/board endpoint that returns SVG images
- Mini boards now use simple <img> tags pointing to the SVG endpoint
- SVGs are cached (30s for active games, 1hr for completed)
- Removed client-side MiniBoard.svelte component
- Refactored og-image to use shared buildBoardStateFromMoves
This approach is:
- Simpler (just img tags)
- More performant (server-side rendering, caching)
- Scalable (SVG format)
- Consistent with OG image styling
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>