test(tlsutil): add unit tests with mock TLS server

Add comprehensive tests using local mock TLS server:
- TestCheckTLSVersions: verify TLS 1.0-1.3 detection
- TestCheckTLS12Ciphers: verify cipher categorization
- TestCheckTLS13Ciphers: verify TLS 1.3 cipher detection
- TestCheckPostQuantumKeyExchange: verify PQ key exchange
- TestCipherCheckResultString: verify text output formatting
- TestPQSignatureOIDLookup: verify ML-DSA/SLH-DSA OID lookup
- TestExtractSignatureAlgorithmOID: verify ASN.1 parsing
- TestCheckAll: integration test of full check flow
- TestTLS12CiphersWeakMap/StrongMap: verify cipher maps

Uses self-signed certificates and local TLS listener for fast,
reliable, CI-friendly tests without external dependencies.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: grokify