Add resign feature and redesign homepage sections
- Add boo.sky.go.resign lexicon for resign records
- Each player writes resign to own PDS (respects ownership)
- Add /api/games/[id]/cancel endpoint
- Update OAuth scope for resign collection
- Homepage: 3 sections (Current/Waiting/Archive)
- Game page: resign button, display in move history
- Firehose: listen for resign events
- Fix OAuth callback redirect handling with isRedirect()
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>