v1.13.1

Fixes

• Traefik Manager reported "Storage is not writable" for a static config it can write. A bind-mounted traefik.yml sits in the image's own /app, which is not writable when the container runs as a non-root user. The check now looks at the file it actually writes, and names that file when there is a real problem (#162)
• Running as a non-root user logged Control server error: Permission denied: '/.gunicorn' on every start. Harmless, but it looked like a failure