open.spotify.com/show link with save_connection. Apostra checks the link
with Spotify and saves the show as an offering catalog item for that
advertiser.
The saved catalog item identifies the show for Spotify podcast promotion. Use
that offering with the promotion so Spotify receives the matching
promotion_target_id.
What the connection shows
Read the connection withget(kind: "connection"). For each mapped advertiser,
ownedLinks says whether a Spotify show is available, already linked, or
confirmed absent. This is available to accounts with Creative Engines access.