fix(zsh): guard compdef on target command being installed

On minimal hosts (remote-dev VM, fresh container) several of the
`compdef alias=target` lines fail at login with messages like:

    compdef: unknown command or service: just
    compdef: unknown command or service: systemctl
    compdef: unknown command or service: lsd

— because zsh has no `_just`/`_systemctl`/`_lsd` completion function
loaded when the binary isn't on the system. Wrap each call in a small
helper that checks $commands[<target>] first so absent tools just
silently skip their alias completion instead of spamming the prompt.

1 files changed, 11 insertions, 5 deletions

diff --git a/dot_config/zsh/dot_zshrc b/dot_config/zsh/dot_zshrc
index fda6853..97bb6ac 100644
--- a/dot_config/zsh/dot_zshrc
+++ b/dot_config/zsh/dot_zshrc
@@ -344,11 +344,17 @@ alias gdbr='gdb -ex start --args'
 alias copilot='gh copilot --autopilot --enable-all-github-mcp-tools --yolo --resume'
 
 # ── Alias completions ─────────────────────────────────────────────────────────
-compdef g=git
-compdef j=just
-compdef n=nvim ndiff=nvim nd=nvim nview=nvim nv=nvim
-compdef sys=systemctl ssys=systemctl sysu=systemctl
-compdef l=lsd la=lsd lt=lsd
+# Guard each compdef on the target command being installed; otherwise zsh
+# prints `compdef: unknown command or service: foo` on every login (e.g. on
+# minimal remote-dev VMs where `just`/`lsd` aren't part of the system).
+# Usage: _dot_compdef <target-cmd> <alias>=<target> [<alias>=<target>...]
+_dot_compdef() { (( $+commands[$1] )) && compdef "${@:2}" }
+_dot_compdef git     g=git
+_dot_compdef just    j=just
+_dot_compdef nvim    n=nvim ndiff=nvim nd=nvim nview=nvim nv=nvim
+_dot_compdef systemctl sys=systemctl ssys=systemctl sysu=systemctl
+_dot_compdef lsd     l=lsd la=lsd lt=lsd
+unfunction _dot_compdef
 
 # ── GPG agent ─────────────────────────────────────────────────────────────────
 # Set GPG_TTY to this shell's actual TTY (not the login console) and tell