feat(VSN-2239): add roadmap preview endpoint for driver planning
Add /api/circuit/trip-days/roadmap-preview endpoint that returns structured planning data per driver for a given date range.
- Add DriverRoadmapPreviewResponse, DayRoadmapDTO, RoadmapRowDTO DTOs
- Add getRoadmapPreview() in TripDayService and TripDayImpl with trip rows grouped by period (MATIN / MIDI / APRES_MIDI), including section separators and special rows (Départ / Arrivée / Enchainement)
- Add query in TripDayRepository to fetch trips by driverIds and date range
- Expose the endpoint in TripDayController and TripDayPath constants Closes VSN-2239