docs(nav): the one page on the site with no nav entry

[lywinged]

What this changes

One line in mkdocs.yml. No content change.

docs/rfcs/a2a-delegation-profile.md is the only one of the site's 48 pages with no nav: entry — 47 entries, 48 pages, and this is the page they do not cover.

This is also the same fix already applied once. 8380993 — "Adopt-the-shared-design-system-and-unhide-ten-pages", 2026-08-19 — added exactly ten nav entries, one of them docs/rfcs/composable-zk-assurance.md, which had landed in #162 three days earlier without one. #184 merged four days after that sweep and did not touch mkdocs.yml, so its RFC is in the state the sweep existed to clear. Nothing in #184's description, comments or reviews mentions the nav, so this reads as the same omission rather than a decision.

It is not unreachable, and this PR is not claiming that: CHANGELOG.md links it, examples/delegation-link/README.md links it, it is in sitemap.xml, and the search index carries 13 entries for it. What it has no path from is the navigation.

Measured by reproducing the deployed build rather than a local one — .docs_build assembled the way docs.yml assembles it, the same sed applied to docs_dir, --strict added:

	exit	warnings	pages that link to it
main	0	none	2 — CHANGELOG, and the page itself
with the nav entry	0	none	49 — all of them, via the sidebar

Nothing else moves. Comparing the two site trees file by file: 49 files differ, none added, none removed, and no page loses a link. 48 of them gain exactly one — the sidebar entry. The forty-ninth is the RFC's own page, which gains 17: its table of contents, which the theme renders only for a page it navigates to. Its rendered <article> is byte-identical across the two builds, same SHA-256 and same 35,201 characters, and sitemap.xml and the search index are identical in both.

llms.txt is untouched by design rather than by omission: the llmstxt plugin takes an explicit sections: list, and that list names no RFC at all — composable-zk-assurance.md is absent from it too.

Type of change

• Editorial (typo, link fix, clarification — no normative effect)
• Non-breaking spec change (new optional field, new platform profile, informative addition)
• Breaking spec change (requires 14-day comment period and Project Lead sign-off)
• Schema change
• Example addition

Spec section

None. The RFC is a draft proposal that binds nothing, and its text is not modified.

Checklist

• DCO sign-off on all commits (git commit -s)
• CHANGELOG.md updated (for any normative change) — n/a, no normative change
• Breaking changes marked with <!-- CHANGED: #NNN — description --> in spec text — n/a
• Backward compatibility statement included (for breaking changes) — n/a

[github-actions]

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[imran-siddique]

Verified the claim at pinned main 4785fa77: the nav carries 47 .md entries against 27 pages under docs/, and set-comparing the two lists leaves exactly one page uncovered, docs/rfcs/a2a-delegation-profile.md. That matches your description precisely.

The build evidence is the part that makes this easy to take: the RFC's rendered <article> is byte-identical across both builds, sitemap and search index unchanged, and the only delta is the sidebar entry plus the page's own table of contents. Nothing normative moves.

Non-blocking observation: the llmstxt sections: list naming no RFC at all is worth a separate look, since composable-zk-assurance.md is missing from it too. Not this PR's job.

Approving and merging.