Check a whole itinerary in one call. For each segment: destination country risk score and advisory levels, active alerts within 300 km of the arrival airport (or in the country for a stay) and live status for flights departing within 48 hours; flags lists what needs attention, most severe first. Args: segments = list of {type: 'flight'|'stay', flight?: 'UA1', from_airport?: 'SFO', to_airport?: 'NRT', country?: 'JPN', city?, start?: ISO datetime, end?: ISO datetime}; trip_id optional.