List Trip Saved Items

The two halves of "the user's saves, seen from this trip".

saved_item_ids — saves whose place already lives in this trip's itinerary, matched on the same ids the itinerary de-dups on (Google id first, TripAdvisor id as the fallback). Lets the saved rows render "Added" without an N-request-per-row scan of every trip.

city_matches — saves in the trip's stated destination that are NOT yet on it, decided by the chat agent's saved-places code but on the label rungs only, so the radius that tunes a prompt cannot move a rendered row. One row per place, newest first, in the SAME item shape as GET /saved so clients reuse their saved-row rendering unchanged. The two fields are disjoint by construction. Filled only for a request that asks with include=city_matches: it costs a second scan of the user's saves plus a full item enrichment, which the callers that render only the "Added" state would pay for and discard.