Archive the monolithic route-features spec and replace with 9 focused
OpenSpec changes: multi-day-routes, waypoint-notes (with POI snapping),
undo-redo, local-dev-stack, route-sharing, route-discovery,
activity-photos, osm-overlays, plus the existing changelog and
komoot-import.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
