v9.24.0 — Instagram setup docs

Documents the caspian-instagram codebase end-to-end: INSTALL.md §5 gains an Instagram deploy block (META_APP_ID/META_APP_SECRET secrets, deploy:instagram, Cloud Scheduler, rules, the one-time Meta app + App Review, per-shop IG Professional/Page), and the scaffolded store README --with-instagram block now covers publish/delete + the go-live note. Docs-only — no consumer action required.