feat(headless): Add headless ui primitives package

[alexcarpenter]

Description

• New internal (private: true) package: unstyled, accessible React compound components built on Floating UI
• 8 primitives: Accordion, Autocomplete, Dialog, Menu, Popover, Select, Tabs, Tooltip
• Shared renderElement util enabling consumer render prop overrides + automatic state-to-data-cl-* attribute mapping
• CSS-driven animation system using Web Animations API (getAnimations().finished)
• All tests run in real Chromium via @vitest/browser-playwright

Why a separate package

@clerk/ui uses @emotion/react as its JSX source, which conflicts with the standard react-jsx transform these primitives need. Splitting them out avoids the transform conflict.

Architecture

• Compound components via Object.assign (Select.Trigger, Select.Popup, etc.)
• Positioning/interactions/focus/ARIA delegated to @floating-ui/react
• Zero emitted styles — consumers style via data-cl-* attribute selectors

Checklist

• pnpm test runs as expected.
• pnpm build runs as expected.
• (If applicable) JSDoc comments have been added or updated for any package exports
• (If applicable) Documentation has been updated

Type of change

• 🐛 Bug fix
• 🌟 New feature
• 🔨 Breaking change
• 📖 Refactoring / dependency upgrade / documentation
• other:

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Latest commit: 36dbb3d

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
clerk-js-sandbox	Skipped		Apr 23, 2026 7:09pm