Bootstrap shadcn registry scaffold with initial entries and validation

[cto-new]

Summary

Bootstrap the shadcn registry scaffold for cuicui/ui, introducing registry scaffold, a root components.json, and initial entries to prove the schema works. Exposes registry exports for site/runtime and adds validation tooling to ensure registry integrity.

Details

• Introduced registry under packages/ui/registry with schema.ts, index.ts, and per-section collections; added root components.json for shadcn CLI resolution
• Added initial registry entries for at least one section/category/component (common-ui: Modern Simple Input, Droppable File) mapped to files/meta and wiring exports
• Added packages/ui/registry.ts to export registry surface for @cuicui/ui/registry usage
• Implemented registry-validation.ts and wired into package.json via registry:lint using tsx; replaced deno flow and added tsx as a dev dep
• Added tiny test harnesses to validate registry imports in site and website contexts
• Acceptance: registry modules compile, shadcn CLI validation passes, and no TypeScript unresolved references to removed schema