Update PDFGenerator to accept optional ItineraryItem array and render items in user-specified sortOrder within each day. Adds support for: - Custom items with icon, title, time, and address - Travel segments from ItineraryItem (not just TravelSegment) - Fallback to derived order when no itinerary items provided Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>