fix(street-level): IC8 review of the Street View provider

Google's Maps Platform terms forbid Street View imagery beside non-Google
maps, so the provider declares requiresMapStack: 'photoreal': off Google
3D its chip is dashed with the reason, lookups and opens skip it, and
leaving Google 3D closes its panorama.

- Ground clicks: only a click on the map itself (scenePick.isSurfacePick:
  nothing picked or Google 3D tile content) at street zoom opens Street
  View, and the camera stays put; higher up the hint says to zoom in.
  scenePick.pickGroundPosition replaces the copy in Directions.
- Viewer: poses go out at once and again when the date and address
  arrive, so an open never hangs on that lookup; one lookup per panorama,
  seeded by the nearest lookup; a close settles a pending open; failed
  lookups are asked again; poses follow position changes, not pano_changed.
- Loader: the gm_authFailure handler is installed once, so a retried load
  reports a refusal once.
- Viewer host: a prewarm that lands after another provider took the host
  is released; FIT/FILL availability is set on every open.
- Provider: a refusal while switched off reports no error over another
  photo; SINCE compares against the end of Google's month; messages name
  the referrer and network causes; FLAT says Street View is 360° only.
- The layer row names the key of the providers that are on; the MCP panel
  CSP admits Street View's tiles, control images and photos.
- Tests for each, against fakes that now follow Google's event order; the
  browser gate restores its state, waits instead of sleeping, aims its
  panel clicks and corner drags, and asserts the camera stays put.

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

src/layers/streetLevel/viewerHost.test.mjs

@@ -633,3 +633,29 @@ test('a pose can date its image by month and name its place', async () => {
     ['day', null],
   );
 });
+
+test('a prewarm that lands after another provider took the host is released, not built under it', async () => {
+  const { state, host, mapillary } = twoProviders();
+  let release;
+  mapillary.prewarm = () =>
+    new Promise((resolve) => {
+      release = resolve;
+    });
+  const warming = host.prewarm([state.providers.get('mapillary')]);
+  await host.open('google', 'g-1'); // the user opens Street View meanwhile
+  release();
+  await warming;
+  assert.equal(mapillary.calls.unmount, 1, 'released at once');
+  // Not kept warm: the next Mapillary open mounts afresh.
+  await host.open('mapillary', 'm-1');
+  assert.equal(state.street.providerId, 'mapillary');
+});
+
+test('FIT/FILL stays hidden for a second Street View panorama after a close', async () => {
+  const { state, host } = twoProviders();
+  await host.open('google', 'g-1');
+  assert.equal(state.street.renderModes, false);
+  host.close();
+  await host.open('google', 'g-2');
+  assert.equal(state.street.renderModes, false);
+});