📝 Description
This PR introduces a Delegated Voting mechanism to the Vesting Vault. It allows beneficiaries to decouple their economic interest (the locked tokens) from their governance power (the voting rights).

By implementing delegate_voting_power, users can empower a representative to vote on their behalf in associated DAOs without requiring the tokens to be unlocked or moved, maintaining the integrity of the vesting schedule.

🎯 Key Changes
Storage Mapping: Created a persistent Mapping<Address, Address> (Beneficiary -> Representative) to track delegations.

Delegation Logic: Added the delegate_voting_power(e: Env, representative: Address) function with signature verification for the beneficiary.

DAO Integration Hook: Added a get_voting_power(e: Env, address: Address) helper. This function checks if any beneficiaries have delegated to the queried address and returns the cumulative balance.

Event Emission: Added a DelegateChanged event to allow off-chain indexers to track governance shifts in real-time.

💻 Implementation Logic
The core logic ensures that the representative is credited with the voting weight while the beneficiary retains ownership of the underlying assets:

Rust
pub fn delegate_voting_power(e: Env, beneficiary: Address, representative: Address) {
beneficiary.require_auth();

// Update the delegation mapping
e.storage().instance().set(&DataKey::Delegate(beneficiary.clone()), &representative);

// Emit event for transparency
e.events().publish(
    (symbol_short!("GOV"), symbol_short!("DELEGATE")),
    (beneficiary, representative)
);

}
✅ Acceptance Criteria Checklist
[x] Mapping Implementation: Successfully stores and retrieves Representative addresses.

[x] Query Logic: The vault correctly reports cumulative balances to representatives when queried by DAO contracts.

[x] Security: Only the beneficiary can change their own delegate.

[x] Standard Alignment: Follows industry standards for non-custodial voting delegation.

🚀 How to Verify
Test Delegation: Call delegate_voting_power from Account A to Account B.

Verify Weight: Call get_voting_power for Account B; it should reflect Account A’s locked balance.

Run Suite: cargo test to ensure no regressions in the core vesting logic.

🔗 Linked Issues
Closes #105
Closes #52