Revert "Try to use QSortFilterProxyModel via cxx-qt."

This reverts commit 325cf285fc.

qml/ClideTreeView.qml

@@ -16,23 +16,20 @@ Rectangle {
 
     signal fileClicked(string filePath)
 
-    // https://doc.qt.io/qt-6/qml-qtquick-treeview.html
     TreeView {
         id: fileSystemTreeView
         anchors.margins: 15
 
         property int lastIndex: -1
 
-        model: FileSystemSortProxyModel {
-            id: fs
-        }
+        model: FileSystem
         anchors.fill: parent
         boundsBehavior: Flickable.StopAtBounds
         boundsMovement: Flickable.StopAtBounds
         clip: true
 
         Component.onCompleted: {
-            fs.setDirectory(root.rootDirectory)
+            FileSystem.setDirectory(root.rootDirectory)
             fileSystemTreeView.expandRecursively(0, -1)
         }
 
@@ -125,13 +122,13 @@ Rectangle {
                     text: qsTr("Set as root index")
                     onTriggered: {
                         console.log("Setting directory: " + treeDelegate.filePath)
-                        FileSystemSortProxyModel.setDirectory(treeDelegate.filePath)
+                        FileSystem.setDirectory(treeDelegate.filePath)
                     }
                 }
                 Action {
                     text: qsTr("Reset root index")
                     onTriggered: {
-                        FileSystemSortProxyModel.setDirectory("")
+                        FileSystem.setDirectory("")
                     }
                 }
             }