Improve readme badges and links

[fern-support]

Important

Improves README.md by adding Fern and npm badges and converting title to Markdown.

• README.md:
  • Replaced HTML title and description with Markdown format for consistency.
  • Added Fern and npm badges with links for quick access to SDK information.

^{This description was created by for 2663738. It will automatically update as commits are pushed.}