feat: implement task management store with IPC integration

- Added a new task store in `src-react/stores/task.ts` to manage tasks and their statuses.
- Implemented functions for creating, executing, and retrying tasks, along with handling task progress and completion.
- Introduced persistence for tasks using IPC.
- Created utility functions for normalizing room types and building subtasks.
- Added a new CSS file for global styles in `src-react/styles.css`.
- Created runtime types in `src-react/types/runtime.ts` and exported them.
- Updated the main entry points for Vue and React applications to support dynamic framework loading.
- Refactored chat model interfaces and utility functions into `src/shared/chat-model.ts`.
- Updated TypeScript configuration to include paths for React components and types.
- Enhanced Vite configuration to support both Vue and React frameworks.

src-react/pages/Cron/index.tsx

@@ -0,0 +1,16 @@
+import PagePlaceholder from '../PagePlaceholder';
+
+export default function CronPage() {
+  return (
+    <PagePlaceholder
+      tag="定时任务"
+      title="定时任务"
+      subtitle="页面结构先沿用当前 Vue 版的内容区布局。"
+      description="后续任务列表、创建弹窗和启停操作会在这个 React 页面壳里逐步替换。"
+      stats={[
+        { label: '页面状态', value: '占位壳' },
+        { label: '迁移策略', value: '沿用现有 UI' },
+      ]}
+    />
+  );
+}