fix(render): release the atmosphere probe's WebGL context

Lose the throwaway WebGL2 probe context right after the link probe instead
of leaving it for GC; browsers (Safari especially) cap live contexts. Note
that affected devices also lose globe-basemap fog, credit the changelog
entry and move it to the top.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

CHANGELOG.md

@@ -1,5 +1,19 @@
 # Changelog
 
+- Render on iPad and iPhone instead of stopping with "An error occurred while
+  rendering." Cesium's per-vertex model atmosphere binds shader `out`
+  parameters directly to varyings, which Apple's Metal/ANGLE backend cannot
+  link, so the program failed and the render loop was torn down. The stage is
+  now kept out of the pipeline on affected devices by clearing
+  `scene.fog.renderable`, which leaves `fog.enabled` — and the fog density that
+  drives 3D Tiles refinement — untouched. Detection is a WebGL2 link probe of
+  the same pattern, so a future driver fix restores the effect with no code
+  change, with iOS/iPadOS detection as a backstop. Sky atmosphere and the
+  ground-atmosphere fragment path route through locals and are unaffected;
+  affected devices lose distance fog on 3D tiles and on the globe basemaps.
+  `src/app/atmosphereCompat.test.mjs` pins the probe, the platform matrix and
+  the `renderable`-not-`enabled` choice (KnottyDyes, #705).
+
 - Region scopes in voice analyst queries ("in the Gulf of Mexico", "over
   the Alps") work again in the dev server: the bundled Natural Earth and
   neighborhood packs are fetched as JSON in the browser
@@ -196,19 +210,6 @@ Analyst records for loaded satellites, datacenters and dams, with explicit bound
   retain geometry; incident-link checks abort on disable or selection change,
   and the row includes a containment legend.
 
-- Render on iPad and iPhone instead of stopping with "An error occurred while
-  rendering." Cesium's per-vertex model atmosphere binds shader `out`
-  parameters directly to varyings, which Apple's Metal/ANGLE backend cannot
-  link, so the program failed and the render loop was torn down. The stage is
-  now kept out of the pipeline on affected devices by clearing
-  `scene.fog.renderable`, which leaves `fog.enabled` — and the fog density that
-  drives 3D Tiles refinement — untouched. Detection is a WebGL2 link probe of
-  the same pattern, so a future driver fix restores the effect with no code
-  change, with iOS/iPadOS detection as a backstop. Sky atmosphere and the
-  ground-atmosphere fragment path route through locals and are unaffected.
-  `src/app/atmosphereCompat.test.mjs` pins the probe, the platform matrix and
-  the `renderable`-not-`enabled` choice.
-
 - Remove the spurious scrollbars that appeared on both panel stacks at narrow
   widths (720px and below) as soon as a panel was expanded. The stacks scroll
   vertically there, and each panel's decorative glow, absolutely positioned