Google: create sitelinks, callouts and other ad extensions

here is no way to attach ad extensions to a campaign created through your API. "sitelink" and "callout" return zero matches across the whole specification.

For search campaigns this is not a cosmetic gap. Extensions are one of the few reliable ways to improve click-through rate, they take up more space in the results, and Google's own quality signals account for them. A campaign built
entirely through your API is therefore structurally weaker than the same campaign built by hand in Google Ads, and that difference is most visible for exactly the small advertisers who benefit most from a tool doing the work for them.

Request: support for sitelinks at minimum, and ideally callouts and structured snippets, either on POST /v1/ads/create or as a separate assets endpoint that can be attached to an existing campaign.

Context that may help prioritise: we are building a guided flow that sets up a first search campaign for small businesses. Everything else we need is there. Extensions are the one remaining thing that makes the result visibly less
good than what a human would build.