Add Markdown report and social media sharing guideline to AI Assistant task

This MR updates the AI Fundamentals and Assistant section by adding:

• A requirement to document the assistant using a README.md in Markdown format.
• A new guideline encouraging participants to share their project on platforms like LinkedIn to collect feedback from real users.

These additions help ensure participants build in public and gather useful insights, while improving documentation practices.

Let me know if you'd like this wording improved or placed under a new heading. Happy to revise!