A fix for selecting with the mouse: shift-click adds to the selection again, and a selection rectangle drawn from empty canvas no longer drags the page along.
typograph.set_interactive() with false and then true, no longer brings back the canvas's
own click handling next to the editor's. The viewer bundle gets the same fix.ed578b3 (from 289a0bc): canvas #219 (TYP-1141), nothing else in the range.DocumentMouseManager by removing its
listeners, but set_interactive(true) → set_enabled(true) attached them again, so both
managers handled every click. Canvas's manager deselected everything and, on empty canvas,
started the viewer's drag-to-pan. editorapp.ts and viewer.ts now call
hand_over_to_host(), after which start_mouse_down() and start_mouse_tracking() attach
nothing. Link mode moves its rubber band through a mousemove listener of its own. Vitest
tests/mouse_manager_handover.test.ts in canvas: 5.