docs: add Shady to Ecosystem Integrations

[shadylabdev]

This PR adds Shady to the Ecosystem Integrations section.

• Shady — Solana privacy toolkit:
  • Stealth Address
  • ZK Gate (view key)
  • Private Swap (Raydium aggregator + ZK access layer)
• Links:
  • 🌐 Website: https://www.shady.to
  • 📘 Docs: https://shadylabs.gitbook.io/shadylabs-docs/
  • 💬 Twitter: https://x.com/Shady_Labs
  • 💻 GitHub: https://github.com/shadylabdev/shady

This highlights Shady as an active privacy-focused dApp within the Solana ecosystem leveraging Elusiv primitives.

[shadylabdev]

Thanks team adding Shady as part of privacy integrations built with Elusiv.
Let me know if you'd prefer this to be in /docs instead of README.