Sharing an X11 Server Across Hosts with FamilyWild

X11 clients fail to connect when run in containers or over SSH because the .Xauthority cookie is keyed to a specific hostname that no longer matches the client's context. By rewriting the cookie's family field from its original value to 0xffff (FamilyWild), a single sed command makes the cookie match any hostname, allowing X11 applications to authenticate successfully regardless of where they're running.