cleanup clipboard history modal

Modals/Clipboard/ClipboardConstants.qml

@@ -0,0 +1,19 @@
+pragma Singleton
+
+import QtQuick
+import Quickshell
+
+Singleton {
+    id: root
+    readonly property int previewLength: 100
+    readonly property int longTextThreshold: 200
+    readonly property int modalWidth: 650
+    readonly property int modalHeight: 550
+    readonly property int itemHeight: 72
+    readonly property int thumbnailSize: 48
+    readonly property int retryInterval: 50
+    readonly property int viewportBuffer: 100
+    readonly property int extendedBuffer: 200
+    readonly property int keyboardHintsHeight: 80
+    readonly property int headerHeight: 40
+}