chore: Removed TMUX and added bash to lab containers

lab/Dockerfile

@@ -2,12 +2,12 @@ FROM git.luke-else.co.uk/luke-else/base:latest
 
 # Install core utilities and development tools
 RUN apk add --no-cache \
+    bash \
     curl \
     git \
     jq \
     openssh \
     openssh-client \
-    tmux \
     sudo \
     ca-certificates \
     busybox-extras \
@@ -32,4 +32,4 @@ WORKDIR /home/dev
 
 RUN sh -c "$(wget -O- https://github.com/deluan/zsh-in-docker/releases/download/v1.2.1/zsh-in-docker.sh)"
 
-CMD [ "tmux" ]
+CMD [ "/bin/zsh" ]