docs: require Vue views, Pinia stores and the kit for new UI

CONTRIBUTING gains a Building UI section: new UX elements are Vue
components rendering a Pinia store their owner publishes to, portable
owners stay framework-free behind a publish option, controls come from
src/ui/kit first, controllers don't bind the DOM by hand (Teleport where a
view renders elsewhere; body classes, focus, same-task measured positions
and painted surfaces stay imperative), text goes through t()/tn() with
msg() for stored English, and tests mount components. The README and the
architecture summary drop the stale vanilla-JS claim, the UI ownership doc
points to the guide, and the migration doc's UiPanel note names
v-panel-state as what draws a panel's collapse.

README.md

@@ -491,12 +491,12 @@ How the globe handles live data:
 - **Sits on the real ground.** Entity heights are aligned to work with Google 3D tiles, so aircraft park on aprons and cameras stand on street corners instead of floating.
 - **Caching and request budgets.** An OpenSky credit governor, a TomTom daily tile budget, and disk-cached TLEs reduce repeated requests. These controls do not replace provider quotas or billing controls.
 - **Server-side credentials.** Every API that touches a private key (OpenAI, AISStream, OpenSky OAuth, camera frames) is brokered through a hardened server-side proxy with SSRF protection, response caps, and sanitized errors. The only keys the browser sees are Google Maps and Cesium ion (restrict both at the provider).
-- **No framework.** Vanilla JavaScript, **CesiumJS**, and **Vite** — plus **Google Photorealistic 3D Tiles** for the planet and the **OpenAI Realtime API** for voice. Fast to read, fast to hack on.
+- **A small stack.** **Vue 3** and **Pinia** for the interface, **CesiumJS** for the globe and **Vite** to build it — plus **Google Photorealistic 3D Tiles** for the planet and the **OpenAI Realtime API** for voice. Fast to read, fast to hack on.
 
 ```
 src/
 ├── main.js                 # Bootstrap: Google 3D tiles, layer registration
-├── ui/                     # Runtime UI — panels, HUD, styles, controls
+├── ui/                     # Runtime UI — Vue views, Pinia stores, kit, controllers, styles
 ├── hud.js                  # Intelligence HUD + AI scene summary
 ├── keySetup.js             # POWER UP panel — in-app provider keys (dev server only)
 ├── mapStackController.js   # Basemap switching — Google 3D / Esri / OSM / ion stacks