Merge origin/main: keep the provider registry, slim it

main grew the Street Level provider registry while this branch removed it
(#982–#985: injected providers, an empty composition, the `r` switch field).
The registry, params, uiState and pick router come back as main has them and
the slimmed layer sits behind the provider contract:

- The core (index.js) drives providers as on main, without surface modes,
  ground casting, FOLLOW, prewarm and nearest-image lookups. A provider's key
  status is asked with a 10 s timeout and asked again on a switch-on while no
  key is known.
- Mapillary is mapillaryProvider.js over the slim coverage, sequences and
  viewer modules, which read the filter and the active flag from the provider
  context.
- The viewer host mounts one provider adapter at a time, no prewarm.
- The panel has a chip per provider again (the pill switches the layer);
  no legend, EXPAND stays the Fullscreen API.
- The contract drops what no provider implements: groundCaster, meshSampler,
  getSurface/setSurface, nearestImage, prewarm, reportError, the legend and
  surface fields of the UI snapshot.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

scripts/format-scope.json

@@ -36,6 +36,10 @@
   "src/main.js",
   "docs/APPLICATION.md",
   "scripts/qa-application.mjs",
+  "scripts/qa-voice-auth.mjs",
+  "scripts/qa-voice-auth-focus.mjs",
+  "src/codexOauthRealtime.test.mjs",
+  "src/voice/cloudVoiceAuth.test.mjs",
   "scripts/qa-terrain-429.mjs",
   "src/app/application.js",
   "src/app/application.test.mjs",
@@ -862,6 +866,20 @@
   "src/ui/streetLevelPresentation.test.mjs",
   "src/app/layers/streetLevel.js",
   "src/tooling/mapillaryProvider.test.mjs",
+  "src/app/layers/streetLevel.test.mjs",
+  "src/data/idSwitches.js",
+  "src/layers/streetLevel/credits.js",
+  "src/layers/streetLevel/mapillaryProvider.js",
+  "src/layers/streetLevel/mapillaryProvider.test.mjs",
+  "src/layers/streetLevel/params.js",
+  "src/layers/streetLevel/params.test.mjs",
+  "src/layers/streetLevel/pickRouter.js",
+  "src/layers/streetLevel/pickRouter.test.mjs",
+  "src/layers/streetLevel/providerSwitches.test.mjs",
+  "src/layers/streetLevel/registry.js",
+  "src/layers/streetLevel/registry.test.mjs",
+  "src/layers/streetLevel/uiState.js",
+  "src/layers/streetLevel/uiState.test.mjs",
   "src/layers/streetLevel/source.test.mjs",
   "src/streetLevelMarkup.test.mjs",
   "src/layers/streetLevel/index.js",