feat(scenes): render the Scene actions panel from a store

The scene interactions owner keeps the pick handler and the interaction
session and presents the panel to the gev-scene-interactions store; the
SceneInteractions view teleports it into the viewer's container with the
same markup and inline styles. Each activation keys its own panel, each
button carries the owner it was rendered for, and only the owner the
store shows may change or remove it.

docs/VUE-MIGRATION.md

@@ -149,7 +149,10 @@ a feature supplying only its accent.
    `gev-status` store; `SplitFlapText` plays the departure-board flip that
    `splitFlap.js` plans, writing only the label's one text node; the toast
    renders what each owner's `createToast()` publishes there, on that
-   owner's own timer), then
+   owner's own timer), the Scene actions panel (`SceneInteractions`
+   teleports what the scene interactions owner publishes to the
+   `gev-scene-interactions` store into the viewer's container; the owner
+   keeps the pick handler and focuses the picked action), 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