TLS HTTP Client

[stephenberry]

TLS HTTP Client

Adds SSL/TLS support to the HTTP client, enabling HTTPS requests for both synchronous and asynchronous APIs.

Changes

include/glaze/net/http_client.hpp

• Introduced socket_variant (std::variant of TCP and SSL socket types) to support both plain and TLS connections throughout the client
• Added ssl_error enum with std::error_code integration for SSL-specific error reporting (e.g., ssl_not_supported, sni_hostname_failed)
• Added detail::socket_is_open and detail::close_socket helpers that operate on the socket variant, with optional graceful SSL shutdown (sends close_notify alert)
• Extended http_connection_pool with SSL context management, is_https connection key discrimination, and thread-safe SSL context access (std::shared_mutex for reader/writer locking)
• Added SSL handshake flows for both sync and async request paths, including SNI hostname support
• Added client-facing APIs: set_ssl_verify_mode, configure_ssl_context, set_graceful_ssl_shutdown
• All SSL functionality is conditionally compiled behind GLZ_ENABLE_SSL

tests/networking_tests/http_client_ssl_test/ (new)

• Dedicated SSL test suite with self-signed certificate generation at runtime
• Covers HTTPS GET/POST, certificate verification, SNI, connection pooling over TLS, and error handling for SSL-disabled builds

tests/networking_tests/CMakeLists.txt

• Added glaze_BUILD_SSL_TESTS option (default ON) to control inclusion of http_client_ssl_test and https_test subdirectories

[packit-as-a-service]

One of the tests failed for 48f5f37. @admin check logs None, packit dashboard https://dashboard.packit.dev/jobs/copr/3195303 and external service dashboard https://copr.fedorainfracloud.org/coprs/build/10069255/