🚀 Overview

This PR introduces advanced managerial and liquidity features to the Vesting-Vault contracts,
scaling the protocol for large organizations and secondary market interoperability.

🛠️ Key Implementations

1. Hierarchical Sub-Vault Delegation (#141, #88)

• Added manager_rights logic allowing a main Admin to delegate a specific token pool (e.g., 50k tokens) to a sub-admin.
• Sub-admins can now distribute and revoke tokens within their assigned pool independently.

2. Vesting Marketplace Listing Hook (#142, #89)

• Implemented authorize_transfer_to_marketplace.
• Enables locking a vault to be represented/traded as an NFT, allowing beneficiaries to access secondary market liquidity without unlocking the underlying tokens.

3. Native XLM Support & Gas Reserving (#143, #90)

• Integrated minimum_reserve_check for XLM-based vaults.
• Gated the final 2 XLM of any allocation to ensure users always have enough gas to process their final "Claim" transaction.

4. Auto-Renewal for Continuous Incentives (#144, #91)

• Added renew_schedule function to extend vesting timelines (e.g., +12 months) for recurring roles like community moderators.

🔗 Closes Issues

Closes #141, #88
Closes #142, #89
Closes #143, #90
Closes #144, #91

Status: Ready for Security Audit.