small code cleanup and added components/ folder for reusable code

shell.qml

@@ -29,11 +29,6 @@ ShellRoot {
         source: Qt.resolvedUrl("polkit/Polkit.qml")
     }
     
-    Component {
-        id: polkitComp
-        Polkit {}
-    }
-
     // ── Spacing Gap: Top / Bottom ────────────────────────────────────────
     Variants {
         model: Quickshell.screens
@@ -101,6 +96,7 @@ ShellRoot {
                 anchors.fill: parent
                 source: {
                     var p = Cfg.Config.theme.wallpaper
+                    if (!p) return ""
                     return p.startsWith("file://") ? p : "file://" + p
                 }
                 fillMode: Image.PreserveAspectCrop