feat(street-level): one imagery source at a time; IC8 review fixes

- One provider is lit at a time: lighting a chip darkens the others, and a
  chip click records every registered provider's switch in one update so
  the share link keeps the swap (also off Google 3D, where Street View is
  not listed). The layer starts with the first default-on provider
  (Mapillary, free); params that light several keep the one already on,
  so reapplying them never flips (litByParams). The now-unreachable
  "several lit" chip paths are gone.
- Leaving Google 3D during a Street View lookup ends it without an error
  or a stuck loading state (openImage's early return resets it; the
  lookup loop rechecks availability).
- A source swap during a lookup no longer reports "no imagery".
- Street View lit off Google 3D says the panel needs the Google 3D map.
- Comments trimmed to the why; keySetupCore.test.mjs back to upstream's
  formatting plus the one new test (was a 551-line reformat).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/layers/streetLevel/providers/google/index.js

@@ -16,11 +16,7 @@ import {
   PICK_PREFIX,
 } from './policy.js';
 
-/**
- * `promise`, unless `ms` pass first (NO_ANSWER_MESSAGE), `signal` aborts, or
- * Google refuses the key: a lookup Google never answers must not keep the
- * panel loading.
- */
+/** `promise`, unless it times out, `signal` aborts or Google refuses the key. */
 function settleWithin(promise, { ms, signal, loader }) {
   return new Promise((resolve, reject) => {
     const timer = setTimeout(
@@ -46,10 +42,8 @@ function settleWithin(promise, { ms, signal, loader }) {
 }
 
 /**
- * Google Street View Street Level provider: Google's own panorama viewer and
- * nearest-panorama lookups. Google offers no coverage layer for other maps,
- * so it draws none; a click on a street opens the panorama there.
- * `getApiKey` returns the browser Maps key; `loader` is ./mapsLoader.js or a stand-in.
+ * Google Street View provider: Google's panorama viewer and nearest-panorama
+ * lookups. It draws no coverage; a click on a street opens the panorama.
  * @returns {import('../../registry.js').StreetLevelProvider}
  */
 export function createGoogleProvider({
@@ -70,19 +64,16 @@ export function createGoogleProvider({
     groundClick: true,
     // Google's terms forbid Street View beside non-Google maps.
     requiresMapStack: FOLLOW_MAP_STACK_ID,
-    // Every panorama is billed to the Maps key: the user lights the chip.
+    // Every panorama is billed to the Maps key.
     defaultOn: false,
-    // Every panorama is 360°, and with no coverage drawn there is nothing
-    // for a date filter to thin: the user picks the place by clicking it.
+    // All 360°, and no coverage for a date filter to thin.
     filters: [],
-    // Google Maps' own look for where a panorama stands and looks.
     marker: Object.freeze({ kind: 'view-cone', color: COLORS.coverage }),
 
     create(context) {
       let keyRequired = !getApiKey();
       let active = false;
       let service = null;
-      /** The one StreetViewService the lookups and the viewer share. */
       async function getService() {
         const lib = await loader.importLibrary('streetView');
         service ||= new lib.StreetViewService();
@@ -94,7 +85,7 @@ export function createGoogleProvider({
         render: context.services?.render,
       });
       const stopAuthWatch = loader.onAuthFailure(() => {
-        // Switched off since: its chip says so; no error over another photo.
+        // Switched off: its chip says so.
         if (context.isActive?.())
           context.actions.reportError(KEY_REJECTED_MESSAGE);
         context.notify();