[davd-gzl]

Before: on Interrail, Railmap searched SNCF's trains only. Paris to Madrid, Amsterdam or Zurich found nothing past the border, and #101 added Renfe by hand.

After: on Interrail, Railmap searches every operator train-api publishes, on the device. An exact trip (one way, round trip, flexible days) finds journeys that change between operators, such as Paris to Madrid with a TGV to Barcelona and then an AVE. Explore from a station lists the towns reachable across Europe. Every station these operators serve is in the station fields and on the map. A Renfe, DB or NS train books on that operator's site ("Book on Renfe") and carries no reservation fee.

It scales by downloading only what a search needs. On a visit the app loads every operator's station list, which is small. Each search then loads only the timetables of the operators on the way: Paris to Madrid loads SNCF and Renfe, never Finland. Settings gains an opt-in "Europe's timetables offline" switch that keeps every country on the device and searches from that copy when there is no connection.

This replaces #101, so #101 can be closed. It needs train-api #14 and #15 merged and deployed. Until /v2/ is published, or whenever it can't be reached and no offline copy is kept, Interrail searches SNCF's trains alone, exactly as before.

How:

• src/europe/engine.ts is a copy of train-api's src/search.ts, with no imports. It matches stations across operators by position and name, groups them into towns, and runs a connection scan.
• src/europe/network.ts builds the station directory from every operator's stations.json.
  • Station ids. A place SNCF serves keeps SNCF's id. Any other place takes the directory's id (amsterdam-centraal). SNCF's stations get their positions from the app's own station list.
  • Picking operators. operatorsFor picks the operators a search needs. Two operators count as linked when they serve the same town. A trip uses every operator on a shortest chain of linked operators between its two towns, or on a chain one operator longer. Explore uses the origin's operators and their neighbours.
  • Search networks. A search network is built over those operators' bundles alone. The last two are kept, so a calendar reuses one.
• src/europe/europe.worker.ts and client.ts load the files and answer searches. Searches the user just asked for go ahead of background work.
  • The days on screen are searched before the first paint.
  • The rest of the bookable days are searched afterwards, and the calendars then fill in.
• Offline mode. Every train-api file goes to Cache Storage (railmap-europe) and is read from there when the network fails. A sync on each visit re-downloads only when train-api's index is newer. Turning it off deletes the copy. public/sw.js leaves that cache alone and no longer caches /v2/ files itself. The cache name is bumped so the new service worker installs.
• findJourneys reads the cached journeys first, through setJourneySource. The trip list, the calendars and the round-trip return lists use them without other changes. A route the network doesn't serve falls back to SNCF's trains.
• Explore keeps SNCF's direct destinations. It then adds the 80 fastest of the 150 busiest towns reachable that day.
• Ideas, arrive-at, multi-city and the planner still search SNCF's trains.
• Booking per operator is ported from Add Spain's Renfe trains to Interrail #101. Operator names are in src/data/operators.ts, and booking sites come from train-api's index.

Tests:

• tests/europe.test.ts covers:
  • station matching, cross-operator journeys and town search;
  • operator picking, and the directory working before any timetable loads;
  • explore ranking and the leg conversion;
  • the findJourneys source, operators and the registry.
• Two browser scenarios run against a stand-in train-api with SNCF, Renfe and Finland's VR:
  • Paris to Madrid goes via Barcelona and the calendar fills in. Finland's timetable is never downloaded. Explore reaches Madrid.
  • The offline switch keeps all three countries' timetables, and a search still finds Paris to Madrid with train-api down.
• npm test (253 tests), build, prerender, generate-pages, verify and test:e2e (27/27) pass locally.