feat(bookings): show transport routes on map (#384, #587)

Adds from/to endpoints to flight/train/cruise/car reservations with
live map rendering. Flights use geodesic arcs and a curved duration +
distance badge; train/car/cruise render as straight or geodesic lines
with endpoint markers. Airports come from an embedded OurAirports
database (~3200 airports, offline-capable); train/cruise/car locations
via Nominatim. Per-trip connection toggle sits in the day plan
sidebar, persisted in localStorage. Clicking a map endpoint opens the
existing transport detail popup. New display setting toggles endpoint
labels on the map. Migration 105 adds the reservation_endpoints table
plus needs_review flag; existing flights are backfilled from their
IATA metadata on server startup.

.gitignore

@@ -16,7 +16,8 @@ client/public/icons/*.png
 *.sqlite-wal
 
 # User data
-server/data/
+server/data/*
+!server/data/airports.json
 server/uploads/
 
 # Environment