feat(docker): enhance Docker deployment setup and configuration

Add comprehensive Docker deployment configuration with:
- New .dockerignore and .llm.env.example files
- Enhanced Dockerfile with multi-stage build and optimizations
- Detailed README with setup instructions and environment configurations
- Improved requirements.txt with Gunicorn
- Better error handling in async_configs.py

BREAKING CHANGE: Docker deployment now requires .llm.env file for API keys

deploy/docker/README.md

@@ -0,0 +1,113 @@
+# Crawl4AI Docker Setup
+
+## Quick Start
+1. Build the Docker image:
+   ```bash
+   docker build -t crawl4ai-server:prod .
+   ```
+
+2. Run the container:
+   ```bash
+   docker run -d -p 8000:8000 \
+     --env-file .llm.env \
+     --name crawl4ai \
+     crawl4ai-server:prod
+   ```
+
+---
+
+## Configuration Options
+
+### 1. **Using .llm.env File**
+Create a `.llm.env` file with your API keys:
+```bash
+OPENAI_API_KEY=sk-your-key
+DEEPSEEK_API_KEY=your-deepseek-key
+```
+
+Run with:
+```bash
+docker run -d -p 8000:8000 \
+  --env-file .llm.env \
+  crawl4ai-server:prod
+```
+
+### 2. **Direct Environment Variables**
+Pass keys directly:
+```bash
+docker run -d -p 8000:8000 \
+  -e OPENAI_API_KEY="sk-your-key" \
+  -e DEEPSEEK_API_KEY="your-deepseek-key" \
+  crawl4ai-server:prod
+```
+
+### 3. **Copy Host Environment Variables**
+Use the `--copy-env` flag to copy `.llm.env` from the host:
+```bash
+docker run -d -p 8000:8000 \
+  --copy-env \
+  crawl4ai-server:prod
+```
+
+### 4. **Advanced: Docker Compose**
+Create a `docker-compose.yml`:
+```yaml
+version: '3.8'
+services:
+  crawl4ai:
+    image: crawl4ai-server:prod
+    ports:
+      - "8000:8000"
+    env_file:
+      - .llm.env
+    restart: unless-stopped
+```
+
+Run with:
+```bash
+docker-compose up -d
+```
+
+---
+
+## Supported Environment Variables
+| Variable               | Description                          |
+|------------------------|--------------------------------------|
+| `OPENAI_API_KEY`       | OpenAI API key                       |
+| `DEEPSEEK_API_KEY`     | DeepSeek API key                     |
+| `ANTHROPIC_API_KEY`    | Anthropic API key                    |
+| `GROQ_API_KEY`         | Groq API key                         |
+| `TOGETHER_API_KEY`     | Together API key                     |
+| `LLAMA_CLOUD_API_KEY`  | Llama Cloud API key                  |
+| `COHERE_API_KEY`       | Cohere API key                       |
+| `MISTRAL_API_KEY`      | Mistral API key                      |
+| `PERPLEXITY_API_KEY`   | Perplexity API key                   |
+| `VERTEXAI_PROJECT_ID`  | Google Vertex AI project ID          |
+| `VERTEXAI_LOCATION`    | Google Vertex AI location            |
+
+---
+
+## Healthcheck
+The container includes a healthcheck:
+```bash
+curl http://localhost:8000/health
+```
+
+---
+
+## Troubleshooting
+1. **Missing Keys**: Ensure all required keys are set in `.llm.env`.
+2. **Permissions**: Run `chmod +x docker-entrypoint.sh` if permissions are denied.
+3. **Logs**: Check logs with:
+   ```bash
+   docker logs crawl4ai
+   ```
+
+---
+
+## Security Best Practices
+- Never commit `.llm.env` to version control.
+- Use Docker secrets in production (Swarm/K8s).
+- Rotate keys regularly.
+
+