Add WaitingForInteraction game stage and Suspended audio state for Emscripten builds.
Audio unlocks and game starts after user clicks or presses any key, satisfying browser
autoplay restrictions while maintaining immediate playback on desktop.
Extends dirty_render_system to detect changes in CursorPosition and TouchState resources. This ensures re-renders trigger immediately when clicking to activate drag functionality, when cursor debug visualization updates, and when cursor fade-out occurs after timeout.
The render dirty flag was being reset instead of accumulated, causing
the game to become stuck and unplayable in web builds. Changed from
assignment to bitwise OR to preserve all dirty state updates.
Also adds game layout component and updates Justfile to build frontend.
