Fix integration reader pages auth-kind-aware boilerplate

The generated reader pages (tools/integration_docs.py) use OAuth-flavoured boilerplate on key-, db- and format-check vendors, which reads wrong (seen on the W3a data-warehouse pages, e.g. Neon, AWS S3). Itemized: 1. "To end access at <Vendor>'s side too, revoke Jaah in <Vendor>'s settings" — for a key/db vendor say to revoke or delete the key/role at the vendor instead. 2. "Agents can do only what the connected <Vendor> account and its granted scopes allow" — drop "granted scopes" when the vendor has no OAuth. 3. "Still stuck? Select Test and read the result: it quotes <Vendor>'s own error" — false for a `kind = "format"` Test (the vendor is never called); word it for format checks. 4. Pages that say the Test "shows who it answered as" for vendors whose Test returns no identity (S3, Redshift) — key the sentence off whether the spec has an identity field. Out of scope: vendor TOML prose; the catalog engine. Done means: `python3 tools/integration_docs.py --write` renders neon.md and aws-s3.md with none of the four sentences above in their OAuth form; `--check` green.

Reader-page boilerplate now follows each vendor's auth and Test: revoke step per kind, scopes only for sign-in, format-Test troubleshooting, identity-gated "answered as". Quick gate green; PR #7896 queued to the lane. Memory: none applied.