collin/mahjong

1. Undo across a hand boundary
undo() is cleared by startHand, so a 下一局 tapped by mistake — and that button sits right under someone's thumb — cannot be taken back. The deal is already reshuffled by then. Would need the snapshot from before nextHand kept, and the seed recorded, so the same wall could be rebuilt.
2. Settings mid-game
設定 is reachable from the lobby and the game-over panel, but not during a 將, so a player who wants to fix a typo'd name has to wait it out. The ? panel is already anchored per-seat and rotated to face its own edge; settings could share that treatment.
3. 花槓 and other flower house rules
Flowers score, but some tables pay 花槓 out the moment it completes rather than at settlement, and some deal 補花 differently at the start. Both are Rules flags plus a payment hook.
- make the scar bgger
- fgure out the br nao
- computer shouldn't be able to take the pung before the throw animation completes
- weirdness around throwing the tiles in the center, it's like attracted to the center, even gets stopped by wall it keeps going
- put the tumble back on a thrown tile — TUMBLE in src/table/pool.ts