Add Farcaster/Warpcast support for social link in docs.json

[Emmo00]

Farcaster is a decentralized social network. It works like Twitter—you can post, follow people, and interact—but no single company controls the network.

{
  "$schema": "https://mintlify.com/docs.json",
  "theme": "mint",
  "name": "IfaLabs",
  // ...
  "footer": {
    "socials": {
      "x": "https://x.com/Ifalabs",
      "github": "https://github.com/IFA-Labs",
      "farcaster": "https://farcaster.xyz/ifalabs" // here
    }
  },
 // ...
}