feat(scenes): render the Scene panel's controls from the store

SceneControls no longer takes element handles or writes the Scene panel's
button states, PLAY label, status line, progress bar or runtime chip: it
presents them to the gev-scenes store, and the panel's buttons, scene
select and IMPORT chooser call its actions there. The chooser opens only
while an owner presents the panel and is cleared once its import settles.
On destroy the panel keeps its last status and buttons, without shots or
the runtime chip, as before.

CHANGELOG.md

@@ -91,6 +91,15 @@
   them to the welcome view's `gev-first-run` store (its new `store` option)
   and connects the controls the view's buttons call (samehkhamis).
 
+- `SceneControls` (`./ui/scenes`) no longer takes `elements` or writes the
+  Scene panel's buttons, status, progress or runtime chip: it presents them
+  to the `gev-scenes` store and the panel's buttons call its actions there.
+  `sceneElements`, `presentSceneButtons`, `presentSceneProgress` and
+  `presentSceneRuntime` give way to `sceneButtonsDisabled` and
+  `scenePercent`. It no longer stands down when the page has no Scene
+  panel: ESC still stops a playing scene and the runtime chip still shows
+  (samehkhamis).
+
 ## [0.3.0] — 2026-10-27 — Street Level, On Your Phone, in Your Language
 
 - Show a Street Level view facing 359.5° or more as 0°. The viewer caption