Keyboard: U=undo, N=new game, D=draw, Escape=pause placeholder (logged
only until the pause screen lands). Mouse: left-click on the stock pile
fires DrawRequestEvent. Cursor coordinates are converted via the active
Camera2d's viewport_to_world_2d so the hit-test works under arbitrary
camera setups.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>