Reentrancy Guard Hardening Across All Vaults

Description
Implement a standardized reentrancy guard pattern across all protocol contracts that handle asset transfers to prevent malicious callbacks. Complexity: Medium (150 points) 🛡️

Requirements and Context

• Background: DeFi protocols are often targets of reentrancy attacks during cross-contract calls.
• Success Criteria (Done):
  • Shared ReentrancyGuard module implemented.
  • All external-facing transfer functions use the guard.
  • Tests demonstrating that nested calls to guarded functions fail.

Suggested Execution

• Fork/Branch: security/reentrancy-hardening
• Implementation: Use a transient storage flag or instance storage boolean to track execution status.

Guidelines

• Complexity: Medium (150 points)