feat(ferratas): keep loaded via ferratas in a tile cache on server and device, group segments, own look and count badge

shared/src/index.ts

@@ -118,3 +118,5 @@ export * from './permissions/permissions';
 
 // Via ferratas around a trip, from OpenStreetMap through Overpass (GET /api/trips/:tripId/ferratas).
 export * from './ferratas/ferratas.schema';
+// The 0.05 degree tile grid both ends load, cache and persist the layer on.
+export * from './ferratas/ferrataGrid';