Fix main & improve cursor sync (#101)

frontend/sync-client/src/sync-operations/file-change-notifier.ts

@@ -0,0 +1,15 @@
+import type { RelativePath } from "../persistence/database";
+
+export class FileChangeNotifier {
+	private readonly listeners: ((filePath: RelativePath) => unknown)[] = [];
+
+	public addFileChangeListener(
+		listener: (filePath: RelativePath) => unknown
+	): void {
+		this.listeners.push(listener);
+	}
+
+	public notifyOfFileChange(filePath: RelativePath): void {
+		this.listeners.forEach((listener) => listener(filePath));
+	}
+}