test(api): the tagged-post ad conformance floor (D55) — the ads lane's foundation (3.25.0)

[jacoby149]

What

The ads lane's foundation item: pin the tagged-post ad conformance (D55) with api/tests/test_ads.py.

An ad is a posts doc tagged ad (a leaf-typed offer + a status), not a service — so the API has zero ad-specific branches, and the conformance is that the ad post is indistinguishable from a post except its tag + body fields.

The 5 tests

1. Create — the ad post is written through the existing /v3/create on posts (no ads service, no new endpoint) with tags=["ad"] + the leaf-typed offer + status in the body, attached to the creator's followers group.
2. Feed read — read_documents_in_groups over the followers group returns the ad interleaved with normal posts: same shape, same keys, the ad fields are the only delta.
3. I3 — a non-follower is an access failure (D42 403) and the document query never runs, so the ad is never returned.
4. status — a plain body field the read does not filter: a paused ad comes back exactly like an active one (curation + the renderer filter client-side, D51).
5. SQL-level pin — the feed read query selects the tags column but filters on neither tags nor status (status is a body field, not a column — it cannot be filtered in SQL at all).

Notes

• No production code changed — the API already treats ad posts as posts (verified: no offer / ad-tag branches in api/app/v3/).
• Gates the catalog + composer (both read this).
• 795 API tests green, ruff clean.

KB: knowledge/knowledge-base/web10-v3/social/ads.md (D55) + ads-catalog.md.