feat: add filesystem watcher and rename QtShell object

src/cpp/watcher.hpp

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <qdir.h>
+#include <qfilesystemwatcher.h>
+#include <qobject.h>
+
+class FiletreeWatcher: public QObject {
+	Q_OBJECT;
+
+public:
+	explicit FiletreeWatcher(QObject* parent = nullptr);
+
+	void addPath(const QString& path);
+
+signals:
+	void fileChanged(const QString& path);
+
+private slots:
+	void onDirectoryChanged(const QString& path);
+	void onFileChanged(const QString& path);
+
+private:
+	QFileSystemWatcher watcher;
+};