Add project README with setup and usage details

Introduces a comprehensive README.md describing XDPL, its features, tech stack, installation steps, usage instructions, deployment options, and configuration. This provides essential documentation for new users and contributors.

README.md

@@ -0,0 +1,148 @@
+# XDPL
+
+A lightweight proxy server for DeepL Translator built with [Nitro](https://nitro.unjs.io/), providing a clean API interface to DeepL's translation services.
+
+## Features
+
+- 🚀 Fast and lightweight proxy server
+- 🔒 Secure routing through Nitro
+- 🌐 Full DeepL API compatibility
+- 📦 Easy deployment to various platforms
+- ⚡ Built-in caching and optimization
+
+## Tech Stack
+
+- **Framework**: [Nitro](https://nitro.unjs.io/) - Universal JavaScript server
+- **Runtime**: Node.js
+- **Package Manager**: pnpm
+- **TypeScript**: Full TypeScript support
+
+## Getting Started
+
+### Prerequisites
+
+- Node.js 18+
+- pnpm (recommended) or npm
+
+### Installation
+
+1. Clone the repository:
+
+```bash
+git clone https://github.com/xixu-me/xdpl.git
+cd xdpl
+```
+
+2. Install dependencies:
+
+```bash
+pnpm install
+```
+
+3. Start the development server:
+
+```bash
+pnpm dev
+```
+
+The server will start on `http://localhost:3000`
+
+### Available Scripts
+
+- `pnpm dev` - Start development server with hot reload
+- `pnpm build` - Build for production
+- `pnpm preview` - Preview production build locally
+- `pnpm prepare` - Prepare Nitro types
+
+## Usage
+
+The proxy server forwards all requests to DeepL's API. You can use it as a drop-in replacement for direct DeepL API calls:
+
+```javascript
+// Instead of calling https://www2.deepl.com/jsonrpc
+// Call your deployed proxy
+fetch('https://your-domain.vercel.app/jsonrpc', {
+  method: 'POST',
+  headers: {
+    'Content-Type': 'application/json',
+  },
+  body: JSON.stringify({
+    // Your DeepL API request
+  })
+})
+```
+
+## Deployment
+
+### Deploy to Vercel
+
+[![Deploy with Vercel](https://vercel.com/button)](https://vercel.com/new/clone?repository-url=https://github.com/xixu-me/xdpl)
+
+#### Option 1: One-Click Deploy
+
+Click the "Deploy with Vercel" button above to deploy instantly.
+
+#### Option 2: Manual Deploy via CLI
+
+1. Install Vercel CLI:
+
+```bash
+npm i -g vercel
+```
+
+2. Login to your Vercel account:
+
+```bash
+vercel login
+```
+
+3. Deploy from your project directory:
+
+```bash
+vercel
+```
+
+4. For production deployment:
+
+```bash
+vercel --prod
+```
+
+#### Option 3: Deploy via Git Integration
+
+1. Push your code to a Git repository (GitHub, GitLab, or Bitbucket)
+2. Visit [vercel.com](https://vercel.com) and import your repository
+3. Vercel will automatically detect the Nitro configuration and deploy
+
+#### Vercel Configuration
+
+The project is pre-configured for Vercel deployment. Nitro automatically generates the necessary Vercel configuration during the build process.
+
+### Deploy to Other Platforms
+
+This Nitro application can also be deployed to:
+
+- **Netlify**: `nitro build --preset netlify`
+- **Cloudflare Workers**: `nitro build --preset cloudflare-pages`
+- **AWS Lambda**: `nitro build --preset aws-lambda`
+- **DigitalOcean**: `nitro build --preset digitalocean`
+
+For more deployment options, see the [Nitro deployment documentation](https://nitro.unjs.io/deploy).
+
+## Configuration
+
+The main configuration is in `nitro.config.ts`:
+
+```typescript
+export default defineNitroConfig({
+  routeRules: {
+    "/**": {
+      proxy: "https://www2.deepl.com/**",
+    },
+  },
+});
+```
+
+## License
+
+This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.