fix Garden shell integration

modules/capabilities/dev-tools.nix

@@ -13,6 +13,8 @@
         dontUnpack = true;
         installPhase = ''
           install -Dm755 "$src" "$out/bin/gardenctl"
+          install -d "$out/share/zsh/site-functions"
+          "$out/bin/gardenctl" completion zsh > "$out/share/zsh/site-functions/_gardenctl"
         '';
       };
       gardenlogin = pkgs.stdenvNoCC.mkDerivation {