fix(security): refresh docs dependency graph

[0xjohnnydev]

Problem

The docs dependency graph currently accounts for 29 open Dependabot alerts. Twenty-seven have patched versions; two image-size advisories do not. This is the docs-only part of #2719.

There are no docs-content or application-source changes in this PR.

What changed

• Updated Next.js to 16.2.11.
• Updated the resolved js-yaml, nanoid, PostCSS, Sharp, and tar versions.
• Left image-size at 2.0.2 because both current advisories publish no patched version.

Definition of Done

• Address all 27 currently patchable docs alerts. The updated manifest and lockfile resolve outside their published vulnerable ranges.
• Preserve a reproducible docs install. The committed lockfile accepts a frozen install with pnpm 10.12.3.
• Keep the two unpatched alerts visible. The package audit reports only the two known image-size advisories rather than hiding or dismissing them.
• Confirm the updated dependency graph still produces the docs site. The production build completes from this branch.
• Current-head GitHub Actions pass. All repository Actions triggered by this split pass.
• GitHub confirms the 27 patchable alerts close after merge to main. A draft PR cannot prove final Dependabot closure.

Known limit

GHSA-5p2g-fcmc-qvqq and GHSA-w3rx-r6r6-pgpr remain open because no fixed image-size release is currently available.

Split provenance

This contains the docs files from #2719, unchanged, rebuilt on current main.