perf(wezterm): pre-resolve WEZTERM_HOSTNAME to skip a hostname fork per prompt

wezterm.sh's __wezterm_user_vars_precmd hook forks `hostname` on every
prompt when WEZTERM_HOSTNAME is unset. Setting it once at shell start
avoids that repeated fork.

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

Author: corrupt952

modules/wezterm/default.nix

@@ -3,6 +3,12 @@
 {
   home.packages = [ pkgs.jetbrains-mono ];
 
+  # wezterm.sh's precmd hook forks `hostname` on every prompt when this is
+  # unset. Pre-resolving it here means the fork happens once per shell start.
+  home.sessionVariables = {
+    WEZTERM_HOSTNAME = "\${WEZTERM_HOSTNAME:-$(hostname)}";
+  };
+
   programs.wezterm = {
     enable = true;
     enableZshIntegration = true;