A cursor resting on a panel or outside the window kept whatever it last
pointed at: the ghost, the tunnel preview, the deconstruct tint all stayed
put, because "not hovering" was not a state the build mode could hold. Make
both ghost tiles optional, clear the hover with them, and re-derive it when
the cursor comes back or a mode is entered.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ne3mejABZoLWKLh8fgpM3x
