plugin: rust-side modules + theme services with serde-typed config

shell/applets/AppletActionBar.qml

@@ -1,5 +1,6 @@
 import QtQuick
 import "../services" as S
+import NovaStats as NS
 
 // Action bar for applet-level controls (power toggles, DND, clear-all, etc.)
 // Place at the top of an applet Column. Children are right-aligned action buttons.
@@ -26,6 +27,6 @@ Item {
         anchors.right: parent.right
         anchors.bottom: parent.bottom
         height: 1
-        color: S.Theme.base03
+        color: NS.ThemeService.base03
     }
 }