Bounty: Add Documentation for React.js Frontend

[thunderisme]

Summary

• Replaces the starter-template README with Kleo Connect-specific project documentation.
• Adds setup, environment-variable, route, project-structure, testing, build/deployment, contribution, and troubleshooting sections.
• Documents the current Vite/React/TypeScript/Tailwind stack and provider configuration surface.

Validation

• npm ci --ignore-scripts
• npm test -- --run
• npm run build
• git diff --check

If accepted for the listed documentation bounty, payout details can be provided privately by the GitHub account owner.