MapKit JS under floating panels: keep map.padding synced and reset it on rebuild

When a full-bleed MapKit JS map has frosted panels floating over it, set map.padding = new mapkit.Padding(top, right, bottom, left) to the panels' covered insets (measured from getBoundingClientRect in a ResizeObserver on the map box and the panels, never in render). MapKit then centres setCenterAnimated/showItems/region framing in the visible part and moves its zoom control and compass out from under the panels. Things that still use the whole box need the same insets: your own 'is this place in view' checks (convertPointOnPageToCoordinate at the inset corners) and follow-the-pin logic, otherwise a tracked pin can walk under a panel before the camera moves. If you cache the last insets to skip redundant writes, reset that cache when the map is destroyed and rebuilt (a retry after an auth error), or the new map never gets its padding. MapKit's anchorOffset moves the anchor, not the element: to centre a DOM annotation on its coordinate use DOMPoint(0, -height/2).