feat(bhote-koshi): render the reconstruction panel from a store

The Bhote Koshi layer keeps its panel controls as plain records and
presents them to a store; the context rail renders the panel as its last
child and marks itself while it is on. Controls are bound to the enable
that published them, and an unchanged frame is not sent again.

docs/VUE-MIGRATION.md

@@ -167,7 +167,12 @@ a feature supplying only its accent.
    (`MissionReplayOverlay` teleports into the globe container what the
    launches layer presents through `subscribeReplayOverlay()`, which the
    application shell publishes to the `gev-mission-replay` store, so the
-   portable `./layers/launches` entry needs no Vue), then
+   portable `./layers/launches` entry needs no Vue), the Bhote Koshi
+   reconstruction panel (`BhoteKoshiPanel`, last in the context rail,
+   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
    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