LinkedIn: honour audienceInclude / audienceExclude on campaign create and boost

What we're asking for: accept targeting.audienceInclude (and audienceExclude) on POST /v1/ads/create and POST /v1/ads/boost for LinkedIn, and actually pass it through to LinkedIn.

Why this matters to us: our customers are Dutch SMBs who hand us a list of target companies. We upload that list, enrich it, and create a LinkedIn company-list audience through your audiences endpoints - that whole path works well. But the last step, running a campaign against that audience, doesn't exist on any path today. The audience
sits there, correctly built, and can only be used by leaving our product and opening Campaign Manager.

What happens today: measured on 2026-08-28, create returned 201 with the field silently dropped from the echoed targeting; boost and reach-estimate behaved the same (an invalid segment id didn't change the estimate either). Since your 2026-08-29 deploy it's a clean 400 naming the field, which is a much better failure mode - but the
capability is still missing.

What "done" looks like for us:
- audienceInclude / audienceExclude accepted on create and boost for LinkedIn
- the audience echoed back in the ad's targeting on GET, so we can verify it landed rather than trusting a 201
- the same fields reflected in supply-forecast, bid-pricing and rf-predictions, so a pre-spend sanity check on a company-list audience means something

This was raised in support chat on 2026-08-28; posting it here since you pointed to Featurebase for this one.