- Replaced single `board` state with `boards` map in App.tsx
- Updated state parsing to use `state.boards` instead of `state.board.grid`
- Updated TicTacToeBoard props to accept `boards` instead of `board`
- Safely extracted TicTacToe board using `boards['tictactoe']?.grid ?? null`
- Added loading fallback when board is not yet available
- Updated rendering guards to prevent undefined map errors
This change fully aligns the frontend with the new multi-board MatchState
introduced on the server (supports TicTacToe, Battleship, and future games).
