Span the power widget's open-panel mark across the percentage block

The widget declared no indicator hint, so the mark fell back to 55% of
the slot — sized for a lone icon, too short once the percentage doubles
the block. Hint the glyph's painted width, the way the clock hints its
label width.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

shell/Ui/BarIconButton.qml

@@ -10,6 +10,7 @@ WidgetButton {
   property real opticalSize: Style.bar.iconCanvas
   property bool debugOpticalBounds: Quickshell.env("OMARCHY_DEBUG_BAR_ICONS") === "1"
   readonly property real opticalCenterErrorX: glyph.visible ? glyph.paintedCenterX - opticalCanvas.width / 2 : 0
+  readonly property real glyphPaintedWidth: glyph.visible ? glyph.tightWidth : 0
   readonly property real glyphBaselineY: glyph.visible ? glyph.baselineY : 0
   readonly property int glyphFontSize: glyph.visible ? glyph.renderedFontSize : 0