refactor: complete modal class-based architecture, design system integration, and map editor modularization

src/map-editor-main.ts

@@ -0,0 +1,8 @@
+import './styles/common.css';
+import './styles/map-editor.css';
+import { MapEditor } from './views/MapEditor';
+
+document.addEventListener('DOMContentLoaded', () => {
+  const editor = new MapEditor();
+  editor.init();
+});