feat(globe): render the tilt and north-up buttons from the globe actions store

The camera orientation controls publish whether the map is tilted and the
camera's whole-degree heading instead of writing the buttons' attributes,
and answer tilt and north-up through the globe actions store. The new
GlobeCompass renders the heading, so a rotating camera re-renders only the
compass. The store drops an unchanged camera state and keeps each clear
owner's busy state, so the buttons show the shell that answers them: a
shell replaced by a newer one, or disposed mid-clear, leaves the live
shell's state alone, and an older shell that answers again shows its own.
createOwners gains owns() and ownerOf().

src/ui/shellElements.js

@@ -63,8 +63,6 @@ export function readShellElements(document = globalThis.document) {
     _cctvSourceBadge: document.getElementById('cctv-source-badge'),
     _cctvMeta: document.getElementById('cctv-meta'),
     _cctvSummary: document.getElementById('cctv-summary'),
-    _tiltMapBtn: document.getElementById('tilt-map-view'),
-    _northUpBtn: document.getElementById('north-up-view'),
     _resetGlobeBtn: document.getElementById('reset-globe-view'),
     _cockpitResetGlobeBtn: document.getElementById('cockpit-reset-globe'),
     _locationSearch: document.getElementById('location-search'),