new: ExpandTile & fix: macos Podfile

lib/view/widget/expand_tile.dart

@@ -0,0 +1,12 @@
+import 'package:flutter/material.dart';
+
+const _shape = Border();
+
+class ExpandTile extends ExpansionTile {
+  const ExpandTile({
+    super.key,
+    required super.title,
+    super.children,
+    super.subtitle,
+  }) : super(shape: _shape, collapsedShape: _shape);
+}