feat(street-level): Street View polish — name, filters, legend, marker

- The chip reads GOOGLE STREET VIEW (and its caption link likewise).
- Providers declare the imagery filters they honour (`filters`, default
  pano + since). Street View declares none: every panorama is 360° and it
  draws no coverage to thin, so its lookups ignore the filters and the
  panel hides IMAGERY and SINCE while it is the only lit provider.
- The legend lists only providers that draw coverage lines, with
  Selected only beside one: Street View alone shows no legend.
- Providers may pick their on-globe marker (`marker`); Street View's is a
  Google-blue field-of-view cone from a white-ringed dot, in place of
  GEV's amber pin, and switches back for a Mapillary photo.

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

src/layers/streetLevel/index.test.mjs

@@ -696,7 +696,7 @@ test('with no Mapillary token, the layer points at Street View, on Google 3D onl
   const stats = layer.getStats();
   assert.equal(stats.keyRequired, true);
   assert.deepEqual(stats.keyAlternatives, [
-    { id: 'google', label: 'STREET VIEW', requiresKeyId: 'google-maps' },
+    { id: 'google', label: 'GOOGLE STREET VIEW', requiresKeyId: 'google-maps' },
   ]);
   assert.deepEqual(layer.getUIState().keyAlternatives, stats.keyAlternatives);
   stack.switchTo('esri-imagery');