Feat: Stealth Drop Circuit

[shreyas-londhe]

This PR implements the circuit for Stealth Drop using PLUMEs.

Circuit Inputs

• Public Inputs:
  • merkle_root
  • nullifier
  • s
• Private Inputs:
  • merkle_proof
  • merkle_proof_path
  • c
  • message
  • public_key

Circuit Checks

• Verifies that the public_key is included in the public merkle_root.
• Verifies that the nullifier is constructed using the given public_key and message.

[shreyas-londhe]

Please review @Divide-By-0