feat(settings): implement greeter & lockscreen customization options

- New option to customize your font & wallpaper on the LockScreen
- New floating sync button if missed to explicitly sync on greeter changes

quickshell/Modules/Settings/Widgets/SettingsFontDropdownRow.qml

@@ -0,0 +1,33 @@
+pragma ComponentBehavior: Bound
+
+import QtQuick
+import qs.Common
+
+SettingsDropdownRow {
+    id: root
+
+    property string currentFont: ""
+    signal fontSelected(string family)
+
+    property var _families: ["Default"]
+    property bool _enumerated: false
+
+    function _enumerate() {
+        if (_enumerated)
+            return;
+        var fonts = Qt.fontFamilies().filter(f => !f.startsWith("."));
+        fonts.sort();
+        fonts.unshift("Default");
+        _families = fonts;
+        _enumerated = true;
+    }
+
+    enableFuzzySearch: true
+    popupWidthOffset: 100
+    maxPopupHeight: 400
+    options: _families
+    currentValue: (root.currentFont === "" || root.currentFont === Theme.defaultFontFamily) ? "Default" : root.currentFont
+    onValueChanged: value => root.fontSelected(value === "Default" ? "" : value)
+
+    Component.onCompleted: Qt.callLater(_enumerate)
+}