docs(releases): write the curated 17.7.0 release page and upgrade checklist

Adds content/docs/releases/v17/17-7.mdx, compiled from the 323 changesets
the version commit 4e4e881 consumed, the ADR-0087 registry entries added
since 17.6.0 and the five objectui pin moves; wires it into the v17
meta.json, index.mdx and the docs-audit list; and appends one dated
correction to 17-6.mdx for the anonymous-endpoint known issue.

Claude-Session: https://claude.ai/code/session_016tKoy8NJa35Yih1FdzrVmn
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

content/docs/releases/v17/17-6.mdx

@@ -1509,6 +1509,12 @@ Each was open when this page was written.
 - **Anonymous endpoints** stay unable to read or write objects until #21158
   lands — see [the deny
   baseline](#a-caller-that-resolves-no-permission-set-gets-the-deny-baseline-21217-21134-21051).
+  **Correction (2026-10-06):** #21158 will not land. It was closed as not
+  planned on 2026-10-04, on the maintainer's ruling that there is no demand for
+  the `guest` anchor's grants, so in 17.7.0 too an app-declared anonymous
+  endpoint (`authRequired: false`) cannot read or write objects. See [17.6.0's
+  known issues](/docs/releases/v17/17-7#notable-fixes-in-1770) on the 17.7.0
+  page.
 - The [known console issues](#new-in-console-studio--objectui-pins-in-1760) at
   the bundled pin.