Set Europe/Paris timezone in all nuc containers

Applied live to the 5 running containers; install scripts and the
post-install checklist now include the timedatectl step.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

nuc/jellyfin-server.md

@@ -34,6 +34,7 @@ for i in $(seq 1 30); do
 done
 
 incus config set "$CNAME" environment.DEBIAN_FRONTEND=noninteractive
+incus exec "$CNAME" -- timedatectl set-timezone Europe/Paris
 incus config set "$CNAME" environment.DEBCONF_NONINTERACTIVE_SEEN=true
 
 # --- Jellyfin from the official repository -----------------------------------