Migrate to libmicrohttpd 1.0.0 API with new features

Raise minimum libmicrohttpd requirement to 1.0.0 and migrate all
deprecated APIs to their v3 replacements:

- Basic Auth: MHD_basic_auth_get_username_password3,
  MHD_queue_basic_auth_required_response3 with UTF-8 support
- Digest Auth: MHD_digest_auth_check3, MHD_digest_auth_check_digest3,
  MHD_queue_auth_required_response3 with SHA-512/256, userhash,
  nonce binding, and structured digest_auth_result enum

Add new response types: empty_response, pipe_response, iovec_response.

Add external event loop integration (run, run_wait, get_fdset,
get_timeout, add_connection), daemon management (quiesce, get_listen_fd,
get_active_connections, get_bound_port), and numerous new daemon options
(listen_backlog, address_reuse, tcp_fastopen_queue_size, turbo, etc.).

Add conditional WebSocket support via libmicrohttpd_ws.

Add utility functions: reason_phrase, is_feature_supported, get_mhd_version.

Author: etr

src/httpserver/websocket_handler.hpp

@@ -71,6 +71,8 @@ class websocket_handler {
      virtual void on_message(websocket_session& session, std::string_view msg) = 0;
      virtual void on_binary(websocket_session& session, const void* data, size_t len);
      virtual void on_ping(websocket_session& session, std::string_view payload);
+     virtual void on_binary(websocket_session& session, const void* data, size_t len);
+     virtual void on_ping(websocket_session& session, std::string_view payload);
      virtual void on_close(websocket_session& session, uint16_t code, const std::string& reason);
 };
 

src/webserver.cpp

@@ -451,6 +451,7 @@ bool webserver::start(bool blocking) {
     }
 #endif  // HAVE_WEBSOCKET
 
+
     daemon = nullptr;
     if (bind_address == nullptr) {
         daemon = MHD_start_daemon(start_conf, port, &policy_callback, this,