Rules - A road may only start from a crossing where the player has a building, or where one of their roads ends AND no opponent's settlement or city stands. roadConnects ignored opponents' buildings, so a road (the computer's included) could be laid straight past a settlement. Also applies to Road Building. - Enforce the piece supply: 15 roads, 5 settlements, 4 cities. It was unlimited. - Tests: building past a settlement and a city, free roads, own settlement not blocking, and running out of each piece. UI - The layout rescaled the board whenever it became the player's turn, because the action buttons only existed then. Everything outside the board now has a fixed height: the action bar always shows every button (disabled, not absent), the prompt is pinned to two lines, player cards always draw every line, and the dice total is always present. Rule recorded in docs/UI-catan.md. Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01JdMNbY5hLR7FjtfEE712xG