Journey 4: B2B API Booking & Automated Fleet Re-routing

Scenario: A travel agency books a large group via the B2B portal, triggering a capacity issue that requires a vehicle swap and dynamic route adjustment. Actors: Travel Agent (B2B), Dispatcher, Bus Driver.

1. [Commerce] The B2B Transaction: A local travel agency uses the B2B White-Label API to book a group of 10 people onto a nearly full tour (🟡 color-coded as B2B Agency source), working on commission. The system auto-validates the agency's VAT ID against the EU VIES database for reverse-charge compliance.
2. [Commerce → Backoffice] Capacity Conflict: The booking pushes the tour's passenger count to 52, but a 49-seater is currently assigned. The Dispatch Board capacity badge flashes 🔴 "52/49" on the affected ServiceLeg block.
3. [Backoffice] The Swap: The Dispatcher opens the Passenger Reassignment View split-screen. She drags the 54-seater onto the leg and the system automatically remaps all SeatReservation entries to equivalent positions on the new vehicle's seat_map_layout, preserving all B2C and B2B booking references.
4. [Backoffice → Operations] Commercial Re-routing: Because the 54-seater is a heavier, taller 3-axle coach, the change instantly pushes a new profile to the Driver Hub. The Commercial Routing engine automatically recalculates the turn-by-turn navigation for the morning pickup sequence, routing the driver around a low bridge that the previous 49-seater could have cleared.