Saved Item Trips

List the user's trips whose itinerary already contains this saved place.

Powers the pre-checked "Added" rows in the "Add to trip" menu so a place can't be silently double-added. Identity matching (_same_place) tolerates the common asymmetry where a saved import carries a google_place_id but an older itinerary activity carries only a tripadvisor_id. Spine-saved rows (card_data=None) match on the canonical id stamped on activities, falling back to the spine's Google source link for pre-stamp activities.