Add a Cursor rules snippet to the README

[NmadeleiDev]

Add a .cursorrules snippet that auto-includes the prufa-mcp install instructions. Cursor users paste it into their .cursorrules file.

[Rohityadav2005]

Hi @NmadeleiDev! I have a background in Al/ML and work with LLM prompts frequently. I'd love to handle this and draft the. cursorrules snippet for the README. Could you please assign this issue to me?