Feat: implements the UploadTool component for Storacha Console Toolkit

[alikhere]

Overview

This PR implements the UploadTool component for the @storacha/ui-react package, enabling Web3 applications to embed Storacha upload functionality directly in their UI without redirecting users to the console.

What's Added

UploadTool Component

A complete, production-ready upload interface with:

• ✅ Type Selection - Radio buttons for File, Directory, and CAR uploads
• ✅ Drag & Drop - Intuitive drag-and-drop with visual hover feedback
• ✅ Upload Progress - Real-time progress bars and shard tracking
• ✅ Success State - CID display with gateway link and "Upload Another" button
• ✅ Options - Configurable "Wrap In Directory" for single files
• ✅ Information - Public/Permanent data warnings for user awareness
• ✅ Private Spaces - Automatic KMS encryption support
• ✅ Customizable - Full style override support via props

Changes

Core Component

• Added: packages/ui/packages/react/src/UploadTool.tsx (549 lines)
  • Complete upload interface with all states (idle, uploading, success, error)
  • Inline styles matching console design
  • Full TypeScript support

Package Integration

• Updated: packages/ui/packages/react/src/index.ts
  • Exported UploadTool component and types

Testing

• Added: packages/ui/packages/react/test/UploadTool.spec.tsx
  • Unit tests for component rendering and prop behavior

Example Application

• Added: Complete example in packages/ui/examples/react/upload-tool/
  • Full Vite + TypeScript setup
  • README with integration patterns

Documentation

• Updated: packages/ui/examples/react/README.md
  • Added UploadTool to examples list

Testing

• ✅ All linter checks passing
• ✅ Unit tests included and passing
• ✅ Example application runs successfully

Closes storacha/console-toolkit#1
Part of storacha/console-toolkit#2

[alikhere]

Closing this as the PR moved to storacha/console-toolkit#12