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/policy.js

@@ -2,14 +2,12 @@ import { COLORS as SHARED_COLORS, PROVIDER_COLORS } from '../../policy.js';
 
 export { NEAREST_RADIUS_M } from '../../policy.js';
 
-/** Identity of the Google Street View street-level provider. */
 export const GOOGLE_PROVIDER_ID = 'google';
 export const GOOGLE_NAME = 'Google Street View';
 export const GOOGLE_LABEL = 'GOOGLE STREET VIEW';
 /** The browser Maps key; Street View also needs the Maps JavaScript API on it. */
 export const GOOGLE_KEY_ID = 'google-maps';
 
-/** Every primitive id this provider creates starts with it. */
 export const PICK_PREFIX = Object.freeze({ root: 'gsv:' });
 
 export const COLORS = Object.freeze({
@@ -20,27 +18,20 @@ export const COLORS = Object.freeze({
 export const GOOGLE_CREDIT_HTML =
   'Street View imagery © <a href="https://www.google.com/streetview/" target="_blank" rel="noopener">Google</a>';
 
-/**
- * Shown when Google refuses the key (gm_authFailure): the Maps JavaScript API
- * is not enabled for it, this site is not an allowed referrer, or billing is off.
- */
+/** Shown when Google refuses the key (gm_authFailure). */
 export const KEY_REJECTED_MESSAGE =
   'Google refused GOOGLE_MAPS_API_KEY for Street View — check that the Maps JavaScript API is enabled for it and this site is an allowed referrer';
 
-/** A nearest-panorama lookup that takes longer has failed. */
+/** Past these, a nearest lookup, an open or a details lookup has failed. */
 export const NEAREST_TIMEOUT_MS = 10_000;
-/** A panorama that has not shown by then has failed to open. */
 export const OPEN_TIMEOUT_MS = 20_000;
-/** A panorama-details lookup that takes longer has failed (and can retry). */
 export const DETAILS_TIMEOUT_MS = 10_000;
-/** Minimum pause after a failed panorama-details lookup before a view can retry. */
+/** Pause after a failed details lookup before a view event can retry. */
 export const DETAILS_RETRY_COOLDOWN_MS = 5_000;
 
-/** Google answered nothing: the network, or a key Google ignores. */
 export const NO_ANSWER_MESSAGE =
   'Street View did not answer — check the network, and that the Maps JavaScript API is enabled for GOOGLE_MAPS_API_KEY';
 
-/** Shown while the provider is on, in place of coverage lines it does not have. */
 export const GROUND_CLICK_HINT = 'click a street to open Street View';
 
 /** Deep link to a panorama on Google Maps (Maps URLs). */