Infrastructure: Split docs into ui.w3-kit.com when large enough

[PetarStoev02]

Parent

Part of w3-kit/cli#4 (Phase 5: Scale + Community)

Goal

When the UI component library grows large enough, split it into its own subdomain.

Trigger

• Component count reaches ~30-40
• docs.w3-kit.com becomes hard to navigate with all content

Requirements

• Dedicated UI component documentation site at ui.w3-kit.com
• Component playground / live preview
• Search across components
• Keep docs.w3-kit.com for guides and recipes

[github-actions]

This issue has had no activity in 60 days. Flagging stale.
If it's still relevant, comment or add it to a due-dated milestone within 30 days, otherwise it will be auto-closed.

[PetarStoev02]

Deferred until trigger conditions met (component count ~30-40, navigation pain). Not actionable now — current docs site (shipped in #118) handles existing content comfortably.