Issue: Proposal messages published without author signature, preventing full nodes from verifying authenticity

Issue: Proposal messages published without author signature, preventing full nodes from verifying authenticity: a task in LegoFlow-SWE (Harbor dataset). Summary: When a leader creates and broadcasts a proposal, the message does not include the author’s cryptographic signature. Full nodes that…

The task

**Summary:** When a leader creates and broadcasts a proposal, the message does not include the author’s cryptographic signature. Full nodes that receive the message cannot verify that the proposal was actually generated by the claimed leader, because the validation logic does not check or require a signature. This…

Part of Lego-X/LegoFlow-SWE.