fix the manager

Dockerfile

@@ -11,6 +11,11 @@ RUN mkdir -p /app /defaults \
 RUN ln -snf /usr/share/zoneinfo/Europe/Rome /etc/localtime && \
     echo "Europe/Rome" > /etc/timezone
 
+# The base image may include Docker's apt repository, but this image does not
+# install Docker packages. Disable it so apt updates do not fail on stale keys.
+RUN rm -f /etc/apt/sources.list.d/docker.list \
+    /etc/apt/sources.list.d/download_docker_com_linux_debian.list
+
 RUN apt-get update && \
         DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
           firefox-esr gnumeric xdg-utils \
@@ -255,4 +260,4 @@ RUN chmod +x /entrypoint.sh
 
 # Set entrypoint and default cmd
 ENTRYPOINT ["/entrypoint.sh"]
-CMD ["/init"]
+CMD ["/init"]