Merge origin/main: Google Street View, KartaView and Panoramax on the slim Street Level

Main gained three imagery providers (Google Street View, KartaView,
Panoramax), shared line-coverage, cone and photo-viewer modules, one source
lit at a time and the translated interface. Their shared modules still
carried what this branch removes, so the merge ports them onto it:

- lineCoverage.js is this branch's coverage.js made provider-neutral
  (draped lines near the ground only, the selection drawn over them, key
  and rate-limit blocking); sequenceCones.js is sequences.js the same way.
  Mapillary, KartaView and Panoramax all build on them; Mapillary moves
  back to providers/mapillary/ beside the others.
- No ground casting, mesh sampling, surface modes, FOLLOW, legend, prewarm,
  orbit overview points (Panoramax's density dots included), stale-tile
  swaps or water-filled point budget come back.
- Kept from main because the new providers need them: requiresMapStack and
  attachMapStackController (Street View on Google 3D only), ground clicks,
  openNearest with an optional provider nearestImage, openImage {frame},
  reportError, the view-cone marker (now an SVG glyph), filters /
  coverageLabel / sinceBasis, OPEN STREET VIEW, keyAlternatives and i18n.
- photoViewer.js treats the viewer as expanded when its wrap is full screen
  or the iPhone popover, as EXPAND now is.
- The fixture browser gate keeps its 8 steps and adds one each for
  KartaView and Panoramax; catalogs, docs, boundaries and format scope
  follow.

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

scripts/fixtures/street-level/mapillaryGraph.mjs

@@ -27,6 +27,15 @@ export const THUMB_HOST = 'qa-fixture.mapillary.com';
 
 const METRES_PER_DEG_LAT = 110_540;
 
+/** Ground distance in metres, as the app's metresBetween. */
+export function metresApart(a, b) {
+  const lat = (((a.lat + b.lat) / 2) * Math.PI) / 180;
+  return Math.hypot(
+    (b.lon - a.lon) * 111_320 * Math.cos(lat),
+    (b.lat - a.lat) * METRES_PER_DEG_LAT,
+  );
+}
+
 /**
  * Photos along PHOTO_LINE, south to north; every third one is a panorama.
  * @returns {Array<{id: string, lon: number, lat: number, isPano: boolean, capturedAt: number, compassAngle: number}>}
@@ -108,7 +117,7 @@ const json = (status, body) => ({
 });
 
 let photoBytes = null;
-function photoJpeg() {
+export function photoJpeg() {
   photoBytes ??= readFileSync(new URL('./street-640x320.jpg', import.meta.url));
   return photoBytes;
 }