fix: secure verifyQuizProof to check hash against parameters

[Glam26]

To summarize, here is exactly what was completed:

1. Removed the Timestamp: The non-deterministic timestamp was removed from
   the createQuizProof function payload, allowing the hash to be reproduced
   accurately.
2. Reconstructed and Verified Hash: Added logic to verifyQuizProof that
   reconstructs the hash from the given parameters ( userAddress , quizId ,
   score ) and strictly compares it against the provided hash before
   checking the signature. This prevents proofs from being reused across
   different users or quizzes.

closes #30

[DeFiVC]

Why is a different account commiting in you PR?