post https://api.neynar.com/v2/farcaster/signer/signed_key
Registers an app fid, deadline and a signature. Returns the signer status with an approval url.
Easiest way to start is to clone our repo that has sign in w/ Farcaster and writes:
https://github.com/manan19/example-farcaster-app
Read more about how writes to Farcaster work with Neynar managed signers