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/ui/streetLevelControls.test.mjs

@@ -307,10 +307,12 @@ function panelDom() {
     add(settings, 'div', { id });
   // A missing key gates the filters only; the chips stay outside the gate.
   const controls = add(settings, 'fieldset', { id: 'sl-controls' });
+  const panoRow = add(controls, 'div', { id: 'sl-pano-row' });
   for (const pano of ['all', 'pano', 'flat'])
-    add(controls, 'button', { dataset: { slPano: pano } });
-  add(controls, 'input', { id: 'sl-since' });
-  add(controls, 'output', { id: 'sl-since-label' });
+    add(panoRow, 'button', { dataset: { slPano: pano } });
+  const sinceRow = add(controls, 'div', { id: 'sl-since-row' });
+  add(sinceRow, 'input', { id: 'sl-since' });
+  add(sinceRow, 'output', { id: 'sl-since-label' });
   add(settings, 'ul', { id: 'sl-legend' });
   const metaRow = add(settings, 'div', { classes: ['sl-meta-row'] });
   add(metaRow, 'div', { id: 'sl-coverage-meta' });
@@ -1207,3 +1209,39 @@ test('a refused key on one provider leaves the other chip switchable, and the re
     ]);
     assert.equal(calls.toasts.length, 0);
   }));
+
+test('Street View alone hides the imagery filters and the legend; Mapillary beside it brings them back', () =>
+  withDom(async (dom) => {
+    const state = uiState();
+    const { layer } = stubPanel(dom, state);
+    const shown = () => ({
+      pano: !dom.root.querySelector('#sl-pano-row').hidden,
+      since: !dom.root.querySelector('#sl-since-row').hidden,
+      controls: !dom.root.querySelector('#sl-controls').hidden,
+      legend: !dom.root.querySelector('#sl-legend').hidden,
+    });
+    assert.deepEqual(shown(), {
+      pano: true,
+      since: true,
+      controls: true,
+      legend: true,
+    });
+    layer.publish({
+      ...state,
+      filterControls: { pano: false, since: false },
+      legend: [],
+    });
+    assert.deepEqual(shown(), {
+      pano: false,
+      since: false,
+      controls: false,
+      legend: false,
+    });
+    layer.publish(state);
+    assert.deepEqual(shown(), {
+      pano: true,
+      since: true,
+      controls: true,
+      legend: true,
+    });
+  }));