- New src/lib/routing.ts: keyless OSRM client, travel modes, distance/skate-time formatters
- New RouteDialog: self-contained Leaflet map drawing the route from the user's
location to a spot/shop/event, with a mode toggle and distance/time summary
- Wire the "Directions" buttons on Spot/Shop/Event detail pages to route in-app
instead of opening Google/Apple Maps
Co-authored-by: shakespeare.diy <assistant@shakespeare.diy>
