Add menu-position support for sidebar links

[rezrah]

Before	After

[Copilot]

Pull Request Overview

This PR adds support for a menu-position frontmatter field to control sidebar link ordering.

• Introduces an order field in the FrontMatter type
• Updates sidebar sorting logic to use menu-position from frontmatter
• Provides an example MDX file using menu-position and updates the changelog

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
packages/theme/types.ts	Added order?: number to FrontMatter to represent custom ordering
packages/theme/components/layout/sidebar/Sidebar.tsx	Extended .sort() comparator to prioritize items with menu-position
packages/site/content/content-example/simple.mdx	Added menu-position: 1 to example frontmatter
.changeset/real-pumas-boil.md	Added changelog entry for menu-position support

Comments suppressed due to low confidence (2)

packages/theme/types.ts:34

• [nitpick] The name order is ambiguous compared to the menu-position key used elsewhere. Adopting a consistent identifier (e.g., menuPosition) across the type, frontmatter, and code will improve clarity.

  order?: number

packages/theme/components/layout/sidebar/Sidebar.tsx:85

• The new sorting logic for menu-position isn’t covered by existing tests. Consider adding unit tests for cases with and without menu-position to verify correct ordering.

                .sort((a, b) => {