feat(examples): add UIZZE design system

[samuelbushi]

Summary

• add a format-native UIZZE example under examples/uizze/
• include DESIGN.md, DTCG design_tokens.json, Tailwind v3 output, and an example README
• adapt the public UIZZE design contract into this repository's DESIGN.md schema
• link back to the canonical UIZZE contract and keep the example's product-specific interaction and state guidance intact

Verification

• git diff --check
• npx tsx packages/cli/src/index.ts lint examples/uizze/DESIGN.md
• result: 0 errors, 0 warnings
• design_tokens.json parses as valid JSON

The example is a derived format mapping. The canonical UIZZE contract remains in uizze/uizze; this PR does not change that source or copy the Skill.

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