[Medium] Add zero-knowledge proof validation

[Josie123-Dev]

Task Description

Implement zero-knowledge proof validation in contracts:

• Validate ZK-proofs
• Check proof integrity
• Verify proof correctness
• Return validation result
• Emit validation events

Requirements

• Proof validation
• Integrity check
• Correctness verification
• Result return
• Event emission

Acceptance Criteria

• Proofs are validated
• Integrity is checked
• Correctness is verified
• Result is returned
• Events are emitted

[GBOYEE]

Hi — ZK-proof validation is core to ValidFi's trust model, so getting this right matters. I can implement the validation flow (integrity check, correctness verification, result return, and event emission) in the contracts following the acceptance criteria, and add a small test harness to prove each path. Would love to pick this up if it's available.

[bbkenny]

Hi team, I'm bbkenny. I'd like to work on adding zero-knowledge proof validation to the ValidFi contract. My approach: review the current contract structure and identify integration points for ZKP validation, implement ZKP verification logic following Soroban best practices, write comprehensive tests for valid proofs, invalid proofs, and edge cases, ensure gas-efficient verification to minimize transaction costs, and document the ZKP validation flow and security assumptions. I prioritize secure, well-tested code. Happy to discuss the ZKP scheme you prefer before implementing.