real aliases for the owner, and eza to go with them

The owner's `aliases` block was one line — `alias sz`. Members got a full set from
shell-skel/zshrc and the owner got that. Replaced with the eza ls family, the
oh-my-zsh standards, and n/vim/sz/ld/httpserver.

eza added to all four core package lists. It is in the noble archive at 0.18.2-1,
so this is a package rather than a binary fetch, and Core utils is section 5 — well
before Shell at 26, so `command -v eza` is already true when the block is written.

The eza aliases are GUARDED behind `command -v eza` and the rest are not, and the
asymmetry is deliberate: these replace `ls`. Unguarded, a machine where eza failed
to install has no working `ls` in any new shell, which reads as a broken machine
rather than a missing package. `alias ld=lazydocker` without lazydocker is one
command-not-found when you type it — that can degrade honestly. Same principle
shell-skel/zshrc already holds to.

python3, not python, for httpserver: Ubuntu ships no `python` binary at all, so as
given it would have been a command-not-found on every machine this targets.

Checked the editor block first — it only exports EDITOR/VISUAL/SUDO_EDITOR, so
n and vim do not collide with anything already appended.

KNOWN: append_once returns 1 when its marker is already present, so a machine that
has already run this keeps the old one-line block and gets none of the above. That
is the function working as designed — it exists so a second run does not duplicate
its work, and it cannot tell a stale block from one the owner edited. Fix by hand:
delete the `# >>> machine-setup: aliases >>>` block from ~/.zshrc and re-run
`machine-setup.sh --only Shell`.

Verified: bash -n, zsh -n on the block, the eza guard leaving ls unset when eza is
absent, and vim resolving through n to nvim.

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

scripts/setup/machine-setup/lib/packages.sh

@@ -96,23 +96,23 @@ pkgs_core() {
       # separate decision from removing the tool that wanted it.
       echo curl ca-certificates gnupg git jq unzip \
         apt-transport-https lsb-release software-properties-common \
-        wget zip build-essential python3 btop htop tree tmux ripgrep fd-find net-tools \
+        wget zip build-essential python3 btop htop tree tmux ripgrep fd-find net-tools eza \
         fail2ban unattended-upgrades
       ;;
     pacman)
       echo curl ca-certificates gnupg git jq unzip \
-        wget zip base-devel python btop htop tree tmux ripgrep fd net-tools \
+        wget zip base-devel python btop htop tree tmux ripgrep fd net-tools eza \
         fail2ban
       ;;
     dnf)
       echo curl ca-certificates gnupg2 git jq unzip \
-        wget zip python3 btop htop tree tmux ripgrep fd-find net-tools \
+        wget zip python3 btop htop tree tmux ripgrep fd-find net-tools eza \
         fail2ban
       ;;
     brew)
       # curl, unzip and the TLS roots ship with macOS; the compilers come from
       # the Xcode command line tools, which is not a formula — see xcode_clt_*.
-      echo gnupg git jq wget btop htop tree ripgrep fd
+      echo gnupg git jq wget btop htop tree ripgrep fd eza
       ;;
   esac
 }