refactor: enhance TimerPage layout and functionality; update theme and tokens for improved design consistency

- Refactored TimerPage component to improve layout and user experience.
- Updated theme configuration to utilize design tokens for better maintainability.
- Introduced new tokens for colors and typography to align with design principles.
- Simplified state management and improved timer functionality.
- Enhanced accessibility and responsiveness of UI elements.

desktop/kadence_desktop/qml/components/PrimaryButton.qml

@@ -1,34 +1,28 @@
-// The filled Material button, painted explicitly.
-//
-// Relying on `highlighted: true` leaves the fill to the style, and under some
-// renderers that fill never appears — white text on a white surface. The
-// primary action on a page is exactly the thing that must never be invisible,
-// so it draws its own pill.
+// The filled button: one per view, painted explicitly so no style can lose it.
 import QtQuick
-import QtQuick.Controls.Material
+import QtQuick.Controls
+
+import ".."
 
 Button {
     id: control
-
-    Material.foreground: "white"
-    font.weight: Font.Medium
-    leftPadding: 20
-    rightPadding: 20
-    implicitHeight: 40
+    implicitHeight: 34
+    leftPadding: 16
+    rightPadding: 16
 
     background: Rectangle {
-        radius: height / 2
-        color: control.enabled ? Material.accent : Material.buttonDisabledColor
+        radius: 8
+        color: control.enabled ? Theme.ember : Theme.rule
         opacity: control.pressed ? 0.82 : (control.hovered ? 0.92 : 1)
-        Behavior on opacity { NumberAnimation { duration: 120 } }
+        Behavior on opacity { NumberAnimation { duration: 110 } }
     }
-
     contentItem: Label {
         text: control.text
-        font: control.font
-        color: control.enabled ? "white" : Material.hintTextColor
+        color: control.enabled ? "white" : Theme.faint
+        font.pixelSize: 13
+        font.weight: Font.Medium
+        font.family: Theme.sansFamily
         horizontalAlignment: Text.AlignHCenter
         verticalAlignment: Text.AlignVCenter
-        elide: Text.ElideRight
     }
 }