refactor: centralize workstation HM base and derive terminal from user metadata

modules/features/_noctalia-config.nix

@@ -1,3 +1,7 @@
+{
+  lib,
+  terminalPackage,
+}:
 {
   settingsVersion = 53;
   bar = {
@@ -255,7 +259,7 @@
     pinnedApps = [ ];
     useApp2Unit = false;
     sortByMostUsed = true;
-    terminalCommand = "kitty -e";
+    terminalCommand = "${lib.getExe terminalPackage} -e";
     customLaunchPrefixEnabled = false;
     customLaunchPrefix = "";
     viewMode = "grid";