v9.22.0 — Instagram publishing

Adds content publishing to the caspian-instagram codebase: new admin callable publishInstagramMedia({ imageUrls, caption }) — 1 image = photo, 2–10 = carousel — via the two-step Graph container/publish flow on the stored Page token; returns { mediaId, permalink }. Requires instagram_content_publish on the token. No consumer action required (additive to the opt-in codebase; redeploy caspian-instagram to pick it up, and reconnect accounts linked before this).