Stream trips as SSE (event: trip per trip, event: done at end). Trips that have booking links but no trip-visible bookings (only failed/voided/cancelled) are omitted; manually created planning trips with zero booking links remain. Every trip is served entirely from stored data — dates, labels, prices, confirmation references, and vendorName on car bookings included; no live provider read happens on this request. holdExpiresAt is always null: hold metadata is not stored. Set MERCURY_TRIPS_SSE_ENABLED=false to fall back to a JSON array.