Config: Add docs covering how each config is consumed and extended

[PetarStoev02]

Context

@w3-kit/config exposes multiple configs (TypeScript, ESLint, Prettier, Tailwind, and soon shared workflows). Today the README is minimal. Each downstream repo needs a clear, copy-paste-ready section showing how to consume and (where appropriate) extend each config.

What to build

Expand this repo's README (or add a docs/ section) covering, per config:

• One-line description
• Install snippet
• Consumption snippet (extends: for TS/ESLint, module.exports = require(...) for Prettier, etc.)
• How to extend or override (e.g., adding project-specific rules)
• Which downstream repos already use it (as live references)

Acceptance criteria

• Each exported config has a documented consumption pattern
• Each config has at least one example of extending/overriding
• README links to the relevant config source files
• No broken links

Pointers

• Existing exports map in package.json
• Live consumers: any of ui, registry, cli, website

Complexity

🟡 Intermediate