Add routeSgrMouseInput() and routeSelectListMouse() to centralize the
repeated SGR parse + SelectList hit-test/hover/wheel/click patterns, and
make SelectList implement MouseRoutable via routeMouse(). The structural
SelectListMouseTarget interface keeps mouse.ts free of component imports.
Extend the emergency-restore tests to assert mouse-off sequences
(1006l/1003l/1000l) are emitted while keeping the alt-screen 1049 gating.