chore: AI Rules for React Spectrum

[reidbarber]

Rules that you can place in your project to help your coding agent (i.e. Cursor) perform better when using various React Spectrum libraries.

✅ 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:

🧢 Your Project:

[rspbot]

Build successful! 🎉

• View the storybook
• View the S2 storybook
• View the documentation

[LFDanLu]

I added the following when using cursor in quarry for the test utils:

## Test writing and test utils
When using server side rendering, the locale prop should be set explicitly on the Provider rather than relying on automatic locale selection.

When writing tests against apps using React Spectrum components, you should try to use the test utils from the `@react-spectrum/test-utils` package. If you are writing tests against apps using React Aria Components, you should try to use the test utils from `@react-aria/test-utils`.

If you are able to browse the web, docs for the test utils can be found at @https://react-spectrum.adobe.com/react-aria/testing.html#react-aria-test-utils- and
https://react-spectrum.adobe.com/react-spectrum/testing.html#react-spectrum-test-utils- respectively. Supported aria patterns can be found in the https://react-spectrum.adobe.com/react-spectrum/testing.html#patterns
and https://react-spectrum.adobe.com/react-aria/testing.html#patterns sections, with links pointing to documentation for
each individual pattern. Prioritize using these docs and looking at ".test." files as examples in https://github.com/adobe/react-spectrum for the specific "createTester" pattern when looking up the API usage.

### Patterns
- Combobox
- GridList
- ListBox
- Menu
- Select
- Table
- Tabs
- Tree

which seemed to work pretty decently. Happy to get this merged in as is, but if you have any feedback or would like to include this section as well lemme know