```

feat(dev): 添加开发服务器与热重载支持

- 新增 `npm run dev` 命令，启动带热重载的开发服务器
- 集成 rollup watch 模式与 LiveReload 实现自动刷新
- 添加开发指南 DEVELOPMENT.md，说明项目结构、预览方式及构建流程
- 新增开发预览页面 index.html，用于嵌入展示 sidepanel 内容
- 更新 package.json 和 package-lock.json，引入相关开发依赖
```

rollup.config.js

@@ -1,7 +1,36 @@
-export default {
+import { defineConfig } from 'rollup';
+import resolve from '@rollup/plugin-node-resolve';
+import commonjs from '@rollup/plugin-commonjs';
+import json from '@rollup/plugin-json';
+import livereload from 'rollup-plugin-livereload';
+import serve from 'rollup-plugin-serve';
+
+export default defineConfig({
   input: 'sidepanel/index.js',
   output: {
     file: 'dist/sidepanel.bundle.js',
-    format: 'iife'
+    format: 'iife',
+  },
+  plugins: [
+    resolve(),
+    commonjs(),
+    json(),
+    livereload({
+      watch: ['dist', 'sidepanel'],
+      verbose: false
+    }),
+    serve({
+      open: true,
+      port: 8082,
+      contentBase: ['.', 'sidepanel'],
+      headers: {
+        'Access-Control-Allow-Origin': '*'
+      }
+    }),
+  ],
+  watch: {
+    include: ['sidepanel/**/*'],
+    exclude: ['node_modules/**/*'],
+    clearScreen: false
   }
-};
+});