refactor(quickshell): centralize hardware status polling

home/dot_config/quickshell/bar/Backlight.qml

@@ -1,42 +1,16 @@
 import QtQuick
-import Quickshell
-import Quickshell.Io
 
 Block {
     id: root
 
-    property int percentage: -1
+    required property var service
 
-    visible: percentage >= 0
+    visible: service.brightness >= 0
     blockColor: "#2980b9"
     interactive: true
-    text: "\uf185  " + percentage + "%"
+    text: "\uf185  " + service.brightness + "%"
     onWheel: wheel => {
         const change = wheel.angleDelta.y > 0 ? "+5%" : "5%-";
-        Quickshell.execDetached(["brightnessctl", "set", change]);
-        refreshTimer.restart();
-    }
-
-    Process {
-        id: brightnessQuery
-        command: ["brightnessctl", "-m"]
-        running: true
-
-        stdout: StdioCollector {
-            onStreamFinished: {
-                const fields = text.trim().split(",");
-                root.percentage = fields.length >= 4
-                    ? parseInt(fields[3].replace("%", ""))
-                    : -1;
-            }
-        }
-    }
-
-    Timer {
-        id: refreshTimer
-        interval: 500
-        repeat: true
-        running: true
-        onTriggered: brightnessQuery.running = true
+        service.setBrightness(change);
     }
 }