Add comprehensive security tests for quota management and relay functionality

- Introduced `relay_dual_lock_race_harness_security_tests.rs` to validate user liveness during lock hold and release cycles.
- Added `relay_quota_extended_attack_surface_security_tests.rs` to cover various quota scenarios including positive, negative, edge cases, and adversarial conditions.
- Implemented `relay_quota_lock_eviction_lifecycle_tdd_tests.rs` to ensure proper eviction of stale entries and lifecycle management of quota locks.
- Created `relay_quota_lock_eviction_stress_security_tests.rs` to stress test the eviction mechanism under high churn conditions.
- Enhanced `relay_quota_lock_pressure_adversarial_tests.rs` to verify reclaiming of unreferenced entries after explicit eviction.
- Developed `relay_quota_retry_allocation_latency_security_tests.rs` to benchmark and validate latency and allocation behavior under contention.

src/proxy/tests/handshake_more_clever_tests.rs

@@ -1,7 +1,7 @@
 use super::*;
 use crate::crypto::{sha256, sha256_hmac, AesCtr};
 use crate::protocol::constants::{ProtoTag, RESERVED_NONCE_BEGINNINGS, RESERVED_NONCE_FIRST_BYTES};
-use rand::{RngExt, SeedableRng};
+use rand::{Rng, SeedableRng};
 use rand::rngs::StdRng;
 use std::collections::HashSet;
 use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};