chore: migrate contexts to stores and refresh barrel exports

- Move state management from `src/contexts` to `src/stores` (zustand-based)
- Update barrelsby config to include new stores directory
- Add bottom-sheet and auth-background components
- Auto-open browser on dev server ready in VS Code launch config
- Refresh generated barrel index files

src/stores/chat/index.ts

@@ -1,18 +1,10 @@
 /**
- * @file Chat 公共导出
+ * Chat 状态机公共导出（barrel）
  *
- * 状态机重构后：
- *   - 业务类（Dart 风格 context/reducer/side-effects）已合并到 chat-machine.ts
- *   - 类型由 chat-types.ts 重新导出
- *   - React 入口为 chat-context.tsx（useMachine 包装）
- *   - Context 形状与初始值位于 chat-context.ts
- *   - 事件联合位于 chat-events.ts
- *
- * 注：chat-side-effects.ts 暂未删除（其中 WebSocket 长生命周期逻辑
- * 待下一轮迁移到 fromCallback actor）。
+ * 重新导出 Chat store 的所有公共 API（state / events / machine / React Provider + GuestChatQuota）。
  */
+
 export * from "./chat-state";
 export * from "./chat-context";
 export * from "./chat-events";
-export * from "./chat-types";
-export { chatMachine } from "./chat-machine";
+export * from "./chat-machine";