refactor(street-level): one provider, no orbit overview, no prewarm, simpler tile choice

The layer now owns its Mapillary parts directly: the provider registry,
pick router, multi-provider UI summary, params codec helper and provider
context are gone. createStreetLevelLayer({ source }) builds coverage,
sequences, the nearest-image lookup and the MapillaryJS viewer itself; a
single providerOn switch keeps the share link's `mapillary` option (off
draws nothing), and getParams/setParams keep { mapillary, pano, sinceDays }.

No z0-5 overview points: above 60 km nothing is drawn and the panel says to
zoom in; the proxy now serves only coverage z11-14. Tiles come from the
visible ground within range of the camera, ranked from the ground under it
(no line-of-sight ranking or near-range padding). MapillaryJS loads on the
first photo; viewer prewarm is removed. Key status, a rejected key and a
rate limit share one `blocked` state on coverage.

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

src/layers/streetLevel/providers/mapillary/sequences.test.mjs

@@ -62,11 +62,8 @@ function setup() {
   const state = {
     services: {},
     viewer: {},
-    context: {
-      notify() {},
-      getFilter: () => ({ pano: 'all', sinceMs: null }),
-      actions: { reportError: (message) => errors.push(message) },
-    },
+    filter: { pano: 'all', sinceDays: 0 },
+    notify() {},
     sequence: {
       selectedId: null,
       images: [],
@@ -80,6 +77,7 @@ function setup() {
     coverage: {
       recolorSequence: (id, selected) => colours.push([id, selected]),
     },
+    reportSequenceError: (message) => errors.push(message),
   };
   const sequences = createSequences({ state, source, parts });
   const drawn = () =>