Revamp README Intro & Overview

I maintain an open-source repository called “sesame-ai-in-finance,” a curated collection of Deep Reinforcement Learning and broader AI resources for trading and quantitative finance. The current README does the job, but its introduction and high-level overview feel dated and don’t capture the project’s recent growth.

I need those two sections rewritten so that a first-time visitor immediately understands:

• the purpose and scope of the list
• what sets it apart from other AI-in-finance collections
• how the content is organised (main categories, Chinese mirror, media assets, contribution flow)
• who should use it—researchers, quants, hobbyists, students—and why

Keep everything in one Markdown file, preserving existing badges, heading hierarchy and links. The tone should remain friendly yet authoritative, with concise language and up-to-date terminology (DRL, Gymnasium, JAX/PyTorch, back-testing libraries, etc.). Once you’re done, submit your work as a Git pull request so I can review the diff easily.

That’s the entire scope: just the README’s introduction and overview, no other files changed.