DL3025: Use arguments JSON notation for CMD and ENTRYPOINT

Shell form (CMD command args) wraps your command in /bin/sh -c, which means the process runs as a child of the shell. This prevents proper signal propagation because SIGTERM sent by Docker to stop a container reaches the shell, not your application, causing ungraceful shutdowns. JSON form (CMD ["command", "args"]) runs the process directly so it receives signals correctly.