Add Docker install, drop yazi, harden installer TERM handling

Replace the Docker-aliases-only component with a full install_docker step:
docker.io via apt, systemd enable, docker group membership, and aliases.
Remove yazi from core packages, terminal configs, aliases, and the repo.

Harden install.sh for SSH clients (e.g. Ghostty) that forward unknown TERM
values: fall back through xterm-256color, xterm, screen, dumb, and use
safe_clear in the interactive menu.

Document Ghostty/SSH terminal issues in README, including bash vs zsh ssh()
wrappers and verification steps.

configs/aliases/.aliases

@@ -8,8 +8,6 @@
 alias ll="eza -lag --icons=always --group-directories-first --smart-group --time-style='+%d %b %y %H:%M'"
 # du all items in folder, human readable
 alias dh='du -chs *'
-# yazi file manager
-alias y='yazi'
 # preview/find file using fzf and bat
 alias pf='fzf --preview "bat --color=always {}"'
 # cd to dir using fuzzy finder (fzf)