Add missing headers and finalize Unix domain socket implementation

Co-authored-by: clauspruefer <17313789+clauspruefer@users.noreply.github.com>

Author: Copilot

src/Server.hpp

@@ -6,6 +6,8 @@
 #include <arpa/inet.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
+#include <fcntl.h>
+#include <cerrno>
 
 #include <poll.h>
 #include <thread>