[Engine] Add protocol-level fee-on-transfer logic

[N-thnI]

Description

Core development task for the vero-core-engine module.

Problem Statement

Developing a hardened, audit-ready foundation for the Vero Protocol control plane.

Technical Requirements

• Requirement: Adherence to Soroban/Rust security standards.
• Requirement: Seamless integration with existing contract architecture.

Implementation Guide

• Suggested Approach: Follow the core protocol integration architecture specs.
• Branch Strategy: To begin work, create a feature branch using: git checkout -b feat/engine-core-8
• Affected Areas: src/core/

Acceptance Criteria

• Task successfully implemented
• CI/CD verification passed

Security & Audit Considerations

• Must undergo ZK-ready integrity check.

Definition of Done

• Code reviewed
• CI/CD passed

[GBOYEE]

Hello! I can handle this. I'll add fee-on-transfer logic that correctly adjusts amounts post-transfer. PR shortly.

[Psalmuel01]

I'd like to take this issue. I'll implement protocol-level fee-on-transfer logic in a way that integrates cleanly with the existing transfer flow, ensuring fees are calculated and applied consistently while preserving existing behavior. I'll also add comprehensive tests covering normal transfers, edge cases, and fee calculations to ensure correctness and reliability.

[grantfox-oss]

🦊 GrantFox — @Psalmuel01 has been assigned to this issue as part of the Official Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #106)
2. Your PR will be reviewed by the Vero-protocol maintainers

Good luck! Track your progress on GrantFox.