Newer gunicorn (post-23.0.0) added _get_control_socket_path() which
calls os.path.isabs() on the value — crashing when it is None.
Point the socket to /dev/shm (already used for worker_tmp_dir) so it
is writable inside the container and satisfies the new gunicorn code.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Gunicorn 25.1.0+ enables a 'control_socket' by default, which creates
a root-owned 'gunicorn.ctl' file in the chdir directory. When this
directory is a volume mount (as in our dev/test setups), it causes
permission errors during Docker build context gathering.
This change explicitly sets 'control_socket = None' to prevent the
creation of this file.
