refactor(street-level): drop FOLLOW and Google 3D ground casting

FOLLOW is gone: no setFollow, follow state, map-stack availability or
handoff listener. Opening a photo still frames it with one flight through
the application's deferred navigation (begin/reassert), so a slow photo
never overrides newer navigation and tracking is released as before.

Ground casting is gone: groundCast.js, meshSampler.js, the surface mode,
the draped-to-cast swap and remesh. Coverage lines are always draped
GroundPolylinePrimitives (ClassificationType.BOTH); cones and the marker
clamp to the ground and keep the horizon cull. The terrain/meshFloor/ground
services and meshFloor.visibleTilesetLoaded are no longer needed.

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

src/app/constructCatalog.js

@@ -152,7 +152,6 @@ export function createApplicationCatalog({
         }),
         createApplicationAlpr({ surface, source: sources.alpr }),
         createApplicationStreetLevel({
-          surface,
           sources: { mapillary: sources.mapillary },
         }),
         satellites,

src/app/layers/streetLevel.js

@@ -6,17 +6,9 @@ import * as input from '../../data/inputOwnership.js';
 import * as render from '../../renderGovernor.js';
 
 /** A new provider registers here; its chip, credit and share bit follow. */
-export function createApplicationStreetLevel({ surface, sources }) {
+export function createApplicationStreetLevel({ sources }) {
   return createStreetLevelLayer({
     providers: [createMapillaryProvider({ source: sources.mapillary })],
-    services: {
-      sprites,
-      picking,
-      input,
-      render,
-      ground: surface?.groundFloor ?? null,
-      meshFloor: surface?.meshFloor ?? null,
-      terrain: surface?.terrain ?? null,
-    },
+    services: { sprites, picking, input, render },
   });
 }