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/uiState.js

@@ -15,6 +15,8 @@ import { COLORS } from './policy.js';
  * @property {string} hint
  * @property {string|null} error
  * @property {string} color   The source's one colour.
+ * @property {boolean} [groundClick]   Draws no coverage: opens where the user clicks.
+ * @property {Array<'pano'|'since'>} [filters]   Imagery filters it honours.
  */
 
 /**
@@ -55,9 +57,23 @@ export function keyAlternatives(providers) {
     .map(({ id, label, requiresKeyId }) => ({ id, label, requiresKeyId }));
 }
 
+/**
+ * Which filter controls mean anything: those a switched-on provider honours.
+ * With none switched on, both show (they apply once one is).
+ * @param {Array<ProviderSnapshot>} providers
+ */
+export function filterControls(providers) {
+  const active = providers.filter((p) => p.on);
+  const honoured = (key) =>
+    active.length === 0 ||
+    active.some((p) => (p.filters ?? ['pano', 'since']).includes(key));
+  return { pano: honoured('pano'), since: honoured('since') };
+}
+
 /**
  * The panel snapshot from core state and provider snapshots. The legend has
- * one swatch per active source, then the shared selection colour.
+ * one swatch per active source that draws coverage lines, then the shared
+ * selection colour; a source that only opens where the user clicks has none.
  * @param {{enabled: boolean, filter: object, providers: Array<ProviderSnapshot>, street: object, sequence: object}} input
  */
 export function composeUIState({
@@ -72,12 +88,14 @@ export function composeUIState({
   const active = providers.filter((p) => p.on);
   const { keyRequired, keyRejected, ...coverage } =
     summarizeCoverage(providers);
-  const legend = active.map((provider) => ({
-    key: provider.id,
-    label: provider.name,
-    color: provider.color,
-  }));
-  if (active.length)
+  const legend = active
+    .filter((provider) => provider.groundClick !== true)
+    .map((provider) => ({
+      key: provider.id,
+      label: provider.name,
+      color: provider.color,
+    }));
+  if (legend.length)
     legend.push({ key: 'selected', label: 'Selected', color: COLORS.selected });
   return {
     enabled,
@@ -87,6 +105,7 @@ export function composeUIState({
     keyAlternatives: keyAlternatives(providers),
     keyRejected,
     filter: { ...filter },
+    filterControls: filterControls(providers),
     providers: providers.map((p) => ({ ...p })),
     coverage,
     legend,