mxqi: Forward $LC_CTYPE to remote session

[donald]

Forward the environment variable LC_CTYPE (typically "en_US.UTF-8" in our environment) to the remote session.

Fixes #459

It could be argued, that we should forward LC_* and LANG, because these could also be used to set the character set. However, we don't really support other languages and this might cause more trouble then help. And Mariux currently sets LC_CTYPE. Fix just this specific use case for now until someone else comes up with another use.

[pmenzel]

Hmm, I installed this version on geniux, and requested a session. On stairwaytoheaven, $LANG is empty.

If I normally connect with SSH to geniux from my Debian laptop with LANG=de_DE.UTF-8, then $LANG=C, but I am able to enter UTF-8 characters.

pmenzel@abreu:~$ echo $LANG
de_DE.UTF-8
pmenzel@abreu:~$ ssh pmenzel@geniux.molgen.mpg.de
Last login: Wed Apr 30 11:00:17 2025 from ip5f5af47f.dynamic.kabel-deutschland.de

  #     #                  ###         #     #  geniux
  ##   ##    ##    #####    #   #    #  #   #   system Dell PowerEdge R420
  # # # #   #  #   #    #   #   #    #   # #    cpu    16x E5-2470 @ 2.30GHz
  #  #  #  #    #  #    #   #   #    #    # 64  ram    64.2 GB
  #     #  ######  #####    #   #    #   # #    arch   x86_64 / 64-bit
  #     #  #    #  #   #    #   #    #  #   #   glibc  2.36
  #     #  #    #  #    #  ###   ####  #     #  kernel 5.15.131.mx64.457 #1

  tags: amd mx64 server

  * internet gateway / multiple purpose
  * not a compute server

pmenzel@geniux:~$ echo $LANG
C