Add stress and manual benchmark tests for handshake protocols

- Introduced `handshake_real_bug_stress_tests.rs` to validate TLS and MTProto handshake behaviors under various conditions, including ALPN rejection and session ID handling.
- Implemented tests to ensure replay cache integrity and proper handling of malicious input without panicking.
- Added `handshake_timing_manual_bench_tests.rs` for performance benchmarking of user authentication paths, comparing preferred user handling against full user scans in both MTProto and TLS contexts.
- Included timing-sensitive tests to measure the impact of SNI on handshake performance.

src/proxy/client.rs

@@ -1328,3 +1328,15 @@ mod beobachten_ttl_bounds_security_tests;
 #[cfg(test)]
 #[path = "tests/client_tls_record_wrap_hardening_security_tests.rs"]
 mod tls_record_wrap_hardening_security_tests;
+
+#[cfg(test)]
+#[path = "tests/client_clever_advanced_tests.rs"]
+mod client_clever_advanced_tests;
+
+#[cfg(test)]
+#[path = "tests/client_more_advanced_tests.rs"]
+mod client_more_advanced_tests;
+
+#[cfg(test)]
+#[path = "tests/client_deep_invariants_tests.rs"]
+mod client_deep_invariants_tests;