fix(street-level): expanded photo leaves with panel-hiding modes; EXPAND on iPhone; pill when Mapillary is off

Three regressions from the slimming, found in review:

- Clean View, recording and the cockpit hid the old expanded viewer with
  CSS; native fullscreen sits above all of that, so the photo stayed over the
  globe (and in recordings). While expanded, the panel now watches the
  <body> classes of those modes and leaves full screen when one starts.
- iPhone Safari has no element fullscreen, so EXPAND had disappeared there.
  Where requestFullscreen is missing but popovers exist, EXPAND opens the
  viewer as a top-layer popover sized to the viewport (it stays in the
  panel's DOM; the popover attribute is set only while open, since a closed
  popover is hidden). Checked in Chrome: the popover fills the viewport over
  the panel's backdrop filter.
- Without the provider chips, a layer that was on with Mapillary switched off
  by a share link or tool (`0.m.0`) showed ON and drew nothing. The pill now
  reads OFF with a hint, and pressing it brings Mapillary back without
  switching the layer off.

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

src/ui/streetLevelPresentation.js

@@ -53,8 +53,11 @@ function formatDate(ms) {
   }
 }
 
+/** Whether the layer draws: on, and Mapillary not switched off by a link or tool. */
+const drawing = (state) => state.enabled === true && state.providerOn !== false;
+
 function presentStatus(state) {
-  const pressed = state.enabled === true;
+  const pressed = drawing(state);
   const title = pressed ? 'Turn Street Level off' : 'Turn Street Level on';
   if (state.keyRejected)
     return { text: 'KEY REJECTED', tone: 'warn', pressed, title };
@@ -93,6 +96,8 @@ function presentViewer(state) {
 
 function presentMeta(state) {
   if (!state.enabled) return 'Switch Street Level on to draw its coverage.';
+  if (!drawing(state))
+    return 'Mapillary is off in this view. Switch Street Level on to show it.';
   if (state.sequence.selectedId)
     return state.sequence.loading
       ? 'Loading this sequence…'