Show OSD and sync touchpad steps when scrolling bar widgets (audio, monitor) (#6421)

* Show OSD and sync touchpad steps when scrolling bar widgets

Scrolling the volume or brightness icon in the bar changed the value
directly without ever calling omarchy-osd, so only the keyboard media
keys showed the popup. On top of that, a touchpad's stream of many
small wheel events per finger-drag wasn't matched to a mouse's single
±120 notch per click, so touchpad scrolling felt uncoordinated and
uneven next to the keyboard/mouse behavior.

- shell/plugins/panels/audio/Panel.qml: accumulate raw wheel delta and
  only apply a step once it crosses a full mouse-notch's worth, so
  touchpad and mouse move the volume in identical 5% increments, and
  ping the OSD each time a step actually lands.
- shell/plugins/panels/monitor/Panel.qml: same accumulator for
  brightness, with a 5% floor so scrolling down can never blank the
  screen.
- shell/plugins/osd/Osd.qml: animate the progress bar's width instead
  of snapping, so successive steps glide smoothly.

* Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

* Fix bar wheel OSD behavior

* Normalize scaled wheel events

---------

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
Co-authored-by: David Heinemeier Hansson <david@hey.com>

shell/plugins/osd/Osd.qml

@@ -56,6 +56,8 @@ Item {
 
   function show(iconName, rawMessage, rawValue, rawMax, rawProgressText, rawDuration) {
     var next = OsdModel.stateForShow(iconName, rawMessage, rawValue, rawMax, rawProgressText, rawDuration)
+    // Update before opening so a fresh OSD starts at its new value; only
+    // subsequent updates while it remains open animate the progress bar.
     iconKey = next.iconKey
     maxValue = next.maxValue
     hasProgress = next.hasProgress
@@ -176,6 +178,11 @@ Item {
             height: parent.height
             width: parent.width * (root.hasProgress ? root.value / root.maxValue : 0)
             color: Color.accent
+
+            Behavior on width {
+              enabled: root.opened
+              NumberAnimation { duration: 140; easing.type: Easing.OutCubic }
+            }
           }
         }
         Text {