Trip planner with itinerary

Build a trip planner for personal travel.

Core features:
1. Create a trip: destinations + dates
2. Day-by-day itinerary with places, time, notes, map
3. Save places from a search (Google Places)
4. Shared editing with travel companions
5. Packing list template per trip type

Data: trips, days, places, collaborators.
Must-haves: offline itinerary view, timezone-aware, image per place.