- DogLoader now covers the whole window (dock top + _loading layer),
dims the dashboard behind it ($background 80%), draws a centered
rounded panel with a running ASCII dog and a 🐾 paw trail
- block keyboard bindings (check_action) and drop focus while refreshing;
restore focus to models table afterwards
- removed the docked progress line (covered by the overlay)
- docs updated; tests: full-screen coverage + input blocking