feat(celestial-ring): render the full-globe ring from a store

The celestial ring presents its overlay to a store and the scene chrome
renders it in the globe container, handing back the two canvases the
ring paints. The application shell passes the store in so the keyhole
helpers other packages import stay free of Vue. Without its canvases the
ring still tracks whether the globe is framed and turns itself off.

docs/APPLICATION.md

@@ -210,7 +210,8 @@ such as `provider-settings`, and their hosts are removed. Leaving out
 out `scene-chrome` the before/after imagery dividers (the imagery still splits,
 with no line or handle to move it), the status chips, the toast, the ORBIT
 indicator, the FPS readout, the Scene actions panel, the data-pack attribution
-cards, the wind inspection marker and the Space Missions replay vehicle;
+cards, the wind inspection marker, the Space Missions replay vehicle and
+the full-globe celestial ring;
 leaving out `command-dock` the voice control and its pointer reticle; and
 leaving out `context` the Bhote Koshi reconstruction panel. An unknown
 view name is an error. A host that does not initialize Core's locale passes

docs/VUE-MIGRATION.md

@@ -172,7 +172,12 @@ a feature supplying only its accent.
    renders what the event layer publishes to the `gev-bhote-koshi-panel`
    store: each control's text, hidden, disabled, value and attributes as
    the layer writes them, unchanged frames sending nothing; the rail takes
-   `bhote-event-active` while it shows), then
+   `bhote-event-active` while it shows), the full-globe celestial ring
+   (`CelestialRing` teleports into the globe container what `CelestialRing`
+   in `src/celestialRing.js` publishes to the `gev-celestial-ring` store and
+   hands its two canvases back for the owner to paint; the application shell
+   passes the store in, so the keyhole helpers other packages import need no
+   Vue), then
    Cockpit (in progress: `CockpitBriefing` renders the briefing card's
    pages, cycle toggle, regional news and local conditions, and
    `CockpitContext` the Contact card's scope, navigation, counts, nearest