Boost an existing post/reel as a click-to-WhatsApp ad (WhatsApp CTA on boostPost, or object_story_id on CTWA ads)

For our users click-to-WhatsApp is the dominant ad format have reels that already perform well organically. They want to put budget behind that exact reel with a "Send WhatsApp message" button — keeping the post's likes and comments as social proof. Meta supports this natively (Instagram's Boost button and Ads Manager both allow boosting an existing reel with a WhatsApp messaging CTA when the Page/IG account is paired with a WhatsApp Business number), but there's currently no way to do it through the Zernio API.