Work-in-progress route-builder checkpoint:
- New RouteStatsBar and WaypointDetailPanel components.
- EditMap / ImageDropzone / WaypointTable / builderStore updates.
- Hoist the elevation gain/loss/range helpers out of build-hikes.ts into
src/lib/hikes/elevation.ts so the builder and the build share one
implementation.
Also bundled here (same file, couldn't be split cleanly): build-hikes.ts
now detects each hike's country at build time — 'CH' when a Swiss canton
matched, otherwise an OSM/Nominatim reverse-geocode — and writes it to the
manifest, feeding the new Kanton/Land filter.
