feat(ui): render the status chips and their split-flap labels from a store

ShellFeedback publishes the loading status and the road network chip, and
CctvControls the camera grid chip, to the gev-status store; the scene
chrome renders them. SplitFlapText plays the departure-board cascade that
splitFlap.js plans, writing only the label's one text node, and rests when
its owner is destroyed. setSplitFlapText and disposeSplitFlap are gone.

docs/VUE-MIGRATION.md

@@ -143,7 +143,11 @@ a feature supplying only its accent.
    imagery dividers (`ImagerySplitView`, in the scene chrome, teleports each
    before/after divider that `createImagerySplit` publishes to the
    `gev-imagery-split` store to the body; the split keeps the
-   drag, keyboard, CSS position and scene split), then
+   drag, keyboard, CSS position and scene split), the status chips
+   (the top-center loading status and the road network and camera grid
+   chips render what ShellFeedback and CctvControls publish to the
+   `gev-status` store; `SplitFlapText` plays the departure-board flip that
+   `splitFlap.js` plans, writing only the label's one text node), 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