Split ncli across multiple files in its own directory

modules/ncli/commands/switch.nix

@@ -0,0 +1,40 @@
+# ncli/commands/switch.nix — Specialization switching
+lib:
+
+{}:
+
+{
+  switch_case = ''
+    current=""
+    if [ -f /etc/nixos-tags ]; then
+      current=$(cat /etc/nixos-tags)
+    fi
+
+    if [ "$#" -ge 2 ]; then
+      spec_name="$2"
+      if [ -n "$current" ]; then
+        echo "Already on specialization: $current. Cannot switch directly to '$spec_name'. Please reboot or return to default first."
+      else
+        if [ -d "/run/current-system/specialisation/$spec_name" ]; then
+          echo "Switching to specialization: $spec_name"
+          sudo /run/current-system/specialisation/"$spec_name"/bin/switch-to-configuration test
+        else
+          echo "Error: Specialization '$spec_name' not found."
+          echo "Available specializations:"
+          ls /run/current-system/specialisation/
+        fi
+      fi
+    else
+      if [ -n "$current" ]; then
+        echo "Already on a specialization: $current. To switch, please reboot, or use 'sudo nixos-rebuild switch --flake .' to get back to default, and then switch after."
+      else
+        specs=$(ls /run/current-system/specialisation/)
+        echo "Specializations available:"
+        echo "$specs"
+        echo ""
+        echo "To switch to a specialization, run: 'ncli switch <tag>'"
+      fi
+    fi
+    ;;
+  '';
+}