Multi-signature / approval flow for high-value spends

[Alhaji-naira]

Summary

Let a policy require a second approver (the owner or a designated co-signer) for spends above a threshold. Design the auth model (propose -> approve -> execute) and emit events for each step.

Acceptance criteria

• Threshold + approver configurable
• A spend above threshold requires the extra approval
• Full test coverage of the flow