chore(deps): bump cn to 0.2.5 and externalize it

[lucaspunz]

Summary

• Bump cn to 0.2.5
• Mark cn as external in the library build

Test Plan

• pnpm build
• pnpm lint

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Note

Low Risk
Dependency pin and bundling-only change; no application logic modified.

Overview
Bumps the cn dependency in @mintlify/components from ^0.2.4 to pinned 0.2.5, with the lockfile updated to match.

Build: Rollup now treats cn as external (alongside React), so the library output keeps import references to cn instead of inlining it—consumers resolve the same dependency at install time.

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