Restyle Quickshell settings inputs to match Omarchy aesthetic

Settings dialogs were rendering text/spin/combo controls with Qt's
default light style, which clashed with the dark Omarchy theme — black
text on dark fills, white dropdown popups, rounded corners, and a
pill-style toggle that didn't match the native StyleToggleRow switch.

- Style.qml: collapse all radius tokens to 0 so Noctalia-compat widgets
  inherit Omarchy's sharp-corner convention
- NToggle: rewrite to mirror the native 48x22 switch with accent fill
  and a sliding 16x16 thumb
- NComboBox: skin contentItem, indicator, popup, and delegate so the
  dropdown reads on dark themes
- NSpinBox: add a styled background, contentItem, and up/down indicators
- SettingsPanel calendar form + DynamicSettingsForm string field: drop
  default TextField chrome for the same translucent foreground fill used
  by WidgetCard, accent border on focus

default/quickshell/omarchy-shell/Widgets/NSpinBox.qml

@@ -7,4 +7,69 @@ SpinBox {
   property string label: ""
   font.family: "JetBrainsMono Nerd Font"
   font.pixelSize: Style.fontSizeS
+  editable: true
+  implicitHeight: 32
+  leftPadding: 10
+  rightPadding: 24
+  topPadding: 4
+  bottomPadding: 4
+
+  background: Rectangle {
+    color: Color.mSurfaceVariant
+    border.color: root.activeFocus ? Color.mPrimary : Color.mOutline
+    border.width: Style.borderS
+    radius: Style.radiusS
+  }
+
+  contentItem: TextInput {
+    text: root.displayText
+    font: root.font
+    color: Color.mOnSurface
+    selectionColor: Qt.rgba(Color.mOnSurface.r, Color.mOnSurface.g, Color.mOnSurface.b, 0.35)
+    selectedTextColor: Color.mOnSurface
+    horizontalAlignment: Qt.AlignLeft
+    verticalAlignment: Qt.AlignVCenter
+    readOnly: !root.editable
+    validator: root.validator
+    inputMethodHints: Qt.ImhFormattedNumbersOnly
+  }
+
+  up.indicator: Rectangle {
+    x: root.mirrored ? 0 : root.width - width
+    width: 20
+    height: root.height / 2
+    color: root.up.pressed
+      ? Qt.rgba(Color.mOnSurface.r, Color.mOnSurface.g, Color.mOnSurface.b, 0.16)
+      : root.up.hovered
+        ? Qt.rgba(Color.mOnSurface.r, Color.mOnSurface.g, Color.mOnSurface.b, 0.08)
+        : "transparent"
+    radius: Style.radiusS
+    Text {
+      anchors.centerIn: parent
+      text: "▲"
+      font.family: root.font.family
+      font.pixelSize: 7
+      color: root.up.hovered ? Color.mOnSurface : Color.mOnSurfaceVariant
+    }
+  }
+
+  down.indicator: Rectangle {
+    x: root.mirrored ? 0 : root.width - width
+    y: root.height / 2
+    width: 20
+    height: root.height / 2
+    color: root.down.pressed
+      ? Qt.rgba(Color.mOnSurface.r, Color.mOnSurface.g, Color.mOnSurface.b, 0.16)
+      : root.down.hovered
+        ? Qt.rgba(Color.mOnSurface.r, Color.mOnSurface.g, Color.mOnSurface.b, 0.08)
+        : "transparent"
+    radius: Style.radiusS
+    Text {
+      anchors.centerIn: parent
+      text: "▼"
+      font.family: root.font.family
+      font.pixelSize: 7
+      color: root.down.hovered ? Color.mOnSurface : Color.mOnSurfaceVariant
+    }
+  }
 }