internal: migrate Studio UI styling to Tailwind CSS

[samohovets]

Summary

• add Tailwind CSS v4 and the official Vite integration to Studio
• migrate the complete Studio interface to statically detectable Tailwind utilities and shared utility-only primitives
• keep studio.css limited to Tailwind imports, source registration, and semantic theme tokens
• document the utility-only styling conventions for contributors

Changelog

Public summary:

• None.

Context:

• Establishes Tailwind and shared Studio design tokens for future UI work while preserving the existing interface and responsive behavior.
• Closes Set up Tailwind CSS v4 in Studio #3.

Verification

• pnpm validate
• pnpm --filter @patchwave/studio fmt:check
• pnpm --filter @patchwave/studio build
• pnpm --filter @patchwave/studio test