docs: add S2 audit skill

[reidbarber]

Adds a new spectrum-audit that helps AI agents audit a codebase for Spectrum best practices.

✅ Pull Request Checklist:

• Included link to corresponding React Spectrum GitHub Issue.
• Added/updated unit tests and storybook for this change (for new code or code which already has tests).
• Filled out test instructions.
• Updated documentation (if it already exists for this component).
• Looked at the Accessibility Practices for this feature - Aria Practices

📝 Test Instructions:

Look at the latest Agent Skills Changes comment on this PR. Run the command listed under Install -> React Spectrum S2. In the CLI prompt, select spectrum-audit as the skill to install.

Invoke the skill in your preferred AI tool.

🧢 Your Project:

[rspbot]

Build successful! 🎉

• View the storybook
• View the S2 storybook
• View the S2 docs
• View the React Aria docs

[rspbot]

Build successful! 🎉

• View the storybook
• View the S2 storybook
• View the S2 docs
• View the React Aria docs

[rspbot]

Build successful! 🎉

• View the storybook
• View the S2 storybook
• View the S2 docs
• View the React Aria docs

[rspbot]

Agent Skills Changes

Added (9)

• s2/skills/spectrum-audit/SKILL.md $\color{green}{+63}$
• s2/skills/spectrum-audit/references/checks/01-setup-config.md $\color{green}{+53}$
• s2/skills/spectrum-audit/references/checks/02-component-usage.md $\color{green}{+42}$
• s2/skills/spectrum-audit/references/checks/03-styling.md $\color{green}{+47}$
• s2/skills/spectrum-audit/references/checks/04-accessibility.md $\color{green}{+30}$
• s2/skills/spectrum-audit/references/checks/05-versioning.md $\color{green}{+18}$
• s2/skills/spectrum-audit/references/checks/06-testing.md $\color{green}{+12}$
• s2/skills/spectrum-audit/references/report-template.md $\color{green}{+72}$
• s2/skills/spectrum-audit/references/scoring-rubric.md $\color{green}{+57}$

Modified (1)

• s2/skills/index.json $\color{green}{+16}$

Install

React Spectrum S2:

npx skills add https://d1pzu54gtk2aed.cloudfront.net/pr/9c10833718253786b1c267a2919193106b0dbdb7/

React Aria:

npx skills add https://d5iwopk28bdhl.cloudfront.net/pr/9c10833718253786b1c267a2919193106b0dbdb7/

[LFDanLu]

LGTM, ran locally against our prototypes repo and it caught our UNSAFEs haha.

[devongovett]

maybe we could add reference links to the docs for these so if they fail they have something to look at