Add new examples: with-todos and with-api-fetch

[Serafeim-Katsaros]

New examples included

1. with-todos

A simple React todo application that demonstrates:

• React functional components
• useState hooks
• Basic component composition
• Client-side state management
• Running a small interactive app with Jetpack

2. with-api-fetch

A React example that fetches and displays data from a public REST API.
This example demonstrates:

• Fetching data from an external API
• useEffect and useState hooks
• Rendering async data
• Real-world API usage with Jetpack

Purpose

These examples aim to:

• Make it easier for new users to understand how to use Jetpack
• Provide practical, beginner-friendly reference projects
• Complement the existing examples with more interactive and realistic scenarios