Restore window placement on startup

lib/utils/loop.dart

@@ -0,0 +1,21 @@
+import 'dart:async';
+
+class Loop {
+  static final List<void Function()> _callbacks = [];
+
+  static void start() {
+    Timer.periodic(const Duration(milliseconds: 100), (timer) {
+      for(var func in _callbacks) {
+        func.call();
+      }
+    });
+  }
+
+  static void register(void Function() func) {
+    _callbacks.add(func);
+  }
+
+  static void remove(void Function() func) {
+    _callbacks.remove(func);
+  }
+}