Address reviewer follow-ups: powerProfile detect, slider live-value, glyphs

- powerProfile now hides on machines without power-profiles-daemon by
  checking against the published profile set rather than a never-undefined
  enum, and uses mdi-scale-balance for Balanced (not battery-charging).
- networkPanel renames the QML-keyword-shadowing 'signal' property to
  'signalStrength'; ethernet glyph corrected to mdi-ethernet (not the
  access-point icon).
- workspacesPro indicator color guards against null bar during construction.
- Common.Slider keeps an internal liveValue so external value bindings
  survive a drag; sliders fed from PipeWire/brightnessctl now follow
  external changes after the user interacts.
- audioPanel drops the redundant default-sink PwObjectTracker since the
  candidate-sinks tracker already covers it.
- networkPanel guards scan/connect commands against re-entry while the
  previous Process is running.
- notificationCenter only instantiates its NotificationServer when the
  module is opted in via settings.replaceMako (default off) so it does
  not collide with mako out of the box.
- PopupCard fully opaque while open (previously 0.98) — removes a
  visible ghost outline on first render.
- Drop dead code: calendar trailing MouseArea, weatherFlyout's unused
  parseForecast/forecast property, idleInhibitor's holdSeconds,
  media's scrollAnim.position; gate media's scroll animation off in
  vertical bar mode.

default/quickshell/bar/common/PopupCard.qml

@@ -77,7 +77,7 @@ PopupWindow {
     border.color: root.bar ? root.bar.foreground : "#cacccc"
     border.width: 1
     radius: 0
-    opacity: root.open ? 0.98 : 0
+    opacity: root.open ? 1.0 : 0
 
     Behavior on opacity {
       NumberAnimation { duration: 140; easing.type: Easing.OutCubic }

default/quickshell/bar/common/Slider.qml

@@ -14,6 +14,9 @@ Item {
   property color knobColor: bar ? bar.foreground : "#cacccc"
   property bool dragging: false
   property real trackHeight: 4
+  property real liveValue: value
+
+  onValueChanged: if (!dragging) liveValue = value
 
   signal moved(real value)
   signal released(real value)
@@ -22,7 +25,7 @@ Item {
   implicitHeight: 22
 
   readonly property real range: Math.max(0.0001, maximum - minimum)
-  readonly property real progress: Math.max(0, Math.min(1, (value - minimum) / range))
+  readonly property real progress: Math.max(0, Math.min(1, (liveValue - minimum) / range))
 
   Rectangle {
     id: track
@@ -87,24 +90,25 @@ Item {
     onPressed: function(mouse) {
       root.dragging = true
       var next = valueFromX(mouse.x)
-      root.value = next
+      root.liveValue = next
       root.moved(next)
     }
     onPositionChanged: function(mouse) {
       if (!root.dragging) return
       var next = valueFromX(mouse.x)
-      root.value = next
+      root.liveValue = next
       root.moved(next)
     }
     onReleased: function(mouse) {
       root.dragging = false
-      root.released(root.value)
+      root.released(root.liveValue)
+      root.liveValue = root.value
     }
     onWheel: function(wheel) {
       var delta = wheel.angleDelta.y > 0 ? root.step : -root.step
-      var next = Math.max(root.minimum, Math.min(root.maximum, root.value + delta))
+      var next = Math.max(root.minimum, Math.min(root.maximum, root.liveValue + delta))
       if (root.integer) next = Math.round(next)
-      root.value = next
+      root.liveValue = next
       root.moved(next)
       root.released(next)
     }