feat: state framework maturity and publish release notes

[smiggleworth]

Summary

• add a plain pre-1.0 maturity statement to the homepage and docs landing page
• add a release-notes section to the docs landing page
• make the docs landing table of contents include the new sections
• add regression coverage for maturity and release-note content
• link the homepage to the release notes

The dependency-updates guide already documents the concrete askr update versus askr upgrade behavior; this PR surfaces that distinction from the release notes so upgrade expectations are not implicit.

TDD

• Red: added catalog assertions requiring pre-1.0 maturity wording and non-empty release notes.
• Green: implemented the shared maturity/release-note data and rendered it in the homepage/docs surfaces.

Validation

• npm run check
• git diff --check

Squash merge requested.

[Copilot]

Pull request overview

This PR adds a clear pre-1.0 maturity statement and a small set of release notes to both the docs landing page and the marketing homepage, with a shared data source and a regression test to keep the content from disappearing.

Changes:

• Introduces shared maturityStatement and releaseNotes data for reuse across docs + marketing.
• Renders new “Maturity” and “Release notes” sections on the /docs landing page and wires them into the docs table of contents.
• Adds a docs catalog regression test to ensure the maturity/release-note content remains present.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tests/docs-catalog.test.ts	Adds regression assertions for maturity statement and release note presence.
src/pages/marketing/home.tsx	Displays the maturity statement on the homepage and links to the docs release notes anchor.
src/pages/docs/release-notes.ts	Centralizes maturity statement + release notes data for reuse.
src/pages/docs/page.tsx	Renders “Maturity” and “Release notes” sections on the docs landing page.
src/pages/docs/catalog.ts	Updates the docs landing table of contents to include the new sections.

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