Upgrade OpenSSL 3 support to version 3.5.1

🔧 Updates:
- Updated OpenSSL3BuildConfig to target openssl-3.5.1 (latest release)
- Successfully tested with Homebrew OpenSSL 3.5.1 (July 1, 2025)

✅ Verified:
- All 5 essential elliptic curves supported (P-256, P-384, P-521, X25519, X448)
- 60 cipher suites including 19 EC-based ciphers
- TLS 1.2 and TLS 1.3 support maintained
- Latest security patches from OpenSSL 3.5.1 release

🔮 Post-Quantum Status:
- Infrastructure ready for future PQ algorithm integration
- Current build optimized for traditional EC cryptography
- Compatible with upcoming OpenSSL PQ implementations

Author: jmcrawford45

build_tasks.py

@@ -372,7 +372,7 @@ def exe_path(self) -> Path:
 class OpenSSL3BuildConfig(OpenSslBuildConfig):
     @property
     def _openssl_git_tag(self) -> str:
-        return "openssl-3.0.15"
+        return "openssl-3.5.1"
 
     _OPENSSL_CONF_CMD = (
         "perl Configure {target} zlib no-zlib-dynamic no-shared enable-rc5 enable-md2 enable-gost "