[TEMPLATE] - React-Native+Express-Backend

### What domain will the project template be based on?

Others (please specify in the details)

### If 'Others', please specify the preferred domain.

Mobile Application Development

### Particular directory path for the template.

template/Mobile/React-Native+Express-Backend/

### What tech stacks do you want to include?

- Frontend (Mobile App): React Native
- Backend (API): Express.js (Node.js)
- Database: MongoDB (via Mongoose ORM)
- Networking: Axios for REST API integration
- Auth: JWT-based authentication setup
- Dev Tools: Nodemon, ESLint

### Brief Description

This template scaffolds a Mobile Hybrid App built with React Native for the frontend and Express.js for the backend API.

It enables developers to quickly build mobile applications that communicate with a robust backend server out-of-the-box.

The template will include:
- A pre-configured Express API with sample routes and JWT authentication.
- A React Native mobile interface (login/signup screen, API integration examples).
- Folder structure optimized for scalability (frontend and backend separated).
- Ready-to-run instructions and scripts for local development (`npm run dev` / `yarn start`).

This will help developers prototype full-stack mobile apps instantly using the `universal-box init` command, eliminating the hassle of configuring mobile-backend integration manually.

### 👀 Have you spent some time checking if this issue has been raised before?

- [x] Yes
- [ ] No

### 🏢 Have you read the Code of Conduct?

- [x] I have read the [Code of Conduct](https://github.com/Abhishek-Mallick/universal-box/blob/main/.github/CODE_OF_CONDUCT.md)

### Would you like to work on this issue?

No

模板应创建在目录 'template/Mobile/React-Native+Express-Backend/' 中。首先检查仓库中现有的模板，以了解结构和所需文件。模板需要包含独立的前端（React Native）和后端（Express.js with MongoDB）设置，并包含身份验证和示例界面。检查 'universal-box init' 命令，了解模板的使用方式。确保模板包含清晰的设置说明和运行脚本。

由索引模型根据 Issue 内容生成。