This update addresses a critical security vulnerability by preventing users from canceling documents after they've been fully signed. This ensures the integrity of legal records and provides reliable proof of agreements. The system now automatically disables the cancellation button and blocks backend changes to finished documents, enhancing security and data protection.

Before this commit, users could cancel documents after everyone had signed. This weakened legal records and proof of agreement.

After this commit, the cancel button disappears once signing is complete. We also blocked backend cancellations to keep finished documents permanent and secure.

task-5980337