Add code-server integration with custom configuration

- Remove systemctl commands from Dockerfile (incompatible with containers)
- Add code-server auto-start in entrypoint.sh on port 30145
- Set /mnt as default working directory for code-server
- Configure proper permissions for /mnt directory

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

entrypoint.sh

@@ -23,7 +23,11 @@ echo "user '$XWINDOW_USER' password set."
 
 # change own and permission
 chown $XWINDOW_USER:$XWINDOW_USER /home/$XWINDOW_USER
-chmod 700 /home/$XWINDOW_USER   
+chmod 700 /home/$XWINDOW_USER
+
+# create and set permission for /mnt directory
+mkdir -p /mnt
+chown $XWINDOW_USER:$XWINDOW_USER /mnt   
 
 # add sudo group
 usermod -aG sudo $XWINDOW_USER
@@ -48,6 +52,9 @@ if [ "$SANDBOX_CHECK_EXIT_CODE" -ne 0 ]; then
 fi
 set -e
 
+# start code-server in background
+su - $XWINDOW_USER -c "code-server --bind-addr 0.0.0.0:30145 --auth password /mnt" &
+
 # run program
 /usr/sbin/xrdp-sesman
 /usr/sbin/xrdp --nodaemon