feat: v0.2.4 — 搜索面板全面重设计 + 完整安装文档

### Changed
- 搜索面板：暗色玻璃拟态设计，SVG 图标，流畅动画，改进间距和焦点状态
- README / site：补全 npm / CDN / ESM / CJS / 浏览器五种安装方式

### Fixed
- CI 卡死：移除 setInterval，改用纯事件驱动
- 浮动工具栏定位修正
- 浮动工具栏开关按钮修复

src/index.ts

@@ -1,7 +1,7 @@
 /**
  * MetonaEditor — Type-safe, lightweight Markdown Editor
  * @module metona-editor
- * @version 0.2.3
+ * @version 0.2.4
  */
 
 import { MarkdownEditor } from './core';
@@ -13,7 +13,7 @@ import { animationUtils } from './animations';
 import { DEFAULTS, ICONS, THEMES, EDIT_MODES, DEFAULT_TOOLBAR, TOOLBAR_ACTIONS } from './constants';
 import type { EditMode, ThemeName, ToolbarItem, EditorOptions } from './constants';
 
-const VERSION = '0.2.3';
+const VERSION = '0.2.4';
 
 const globalPlugins: any[] = [];