feat(api): implement OpenAPI/REST API for file conversions

- Add comprehensive REST API at /api/v1 with modular structure
- Implement authentication endpoints (register, login, logout, me)
- Add converter listing and format discovery endpoints
- Create job management and file download endpoints
- Add health check endpoint for monitoring
- Set up CORS support for browser-based API clients
- Create API middleware for JWT authentication
- Add environment variables for API configuration
- Include comprehensive API documentation and test script

Infrastructure:
- Enhanced CI/CD workflow for custom Docker registries
- Docker Compose setup with dev, prod, and monitoring profiles
- Claude.ai integration files for development workflow
- Environment-based configuration with .env.development

Known limitations:
- JWT authentication context needs fixing (using ALLOW_UNAUTHENTICATED=true)
- Swagger UI temporarily disabled due to composition error
- File upload endpoint needs multipart/form-data support

The API code is isolated in src/api/ directory to maintain separation
from the existing codebase, making it easy to maintain or contribute back.

docker-compose.README.md

@@ -0,0 +1,161 @@
+# Docker Compose Configuration
+
+This project includes both `compose.yaml` (original) and `docker-compose.yml` (enhanced) for different use cases.
+
+## Files
+
+- **compose.yaml**: Original simple production deployment
+- **docker-compose.yml**: Enhanced configuration with development, monitoring, and API features
+
+## Quick Start
+
+### Production Mode
+```bash
+# Using original compose file
+docker compose -f compose.yaml up -d
+
+# Using enhanced compose file (production service only)
+docker compose up -d convertx
+```
+
+### Development Mode
+```bash
+# Start development server with hot reload
+docker compose --profile dev up convertx-dev
+
+# Start both production and development
+docker compose --profile dev up
+```
+
+## Services
+
+### convertx (Production)
+- Main application service
+- Port: 3000
+- Includes health checks and auto-restart
+
+### convertx-dev (Development)
+- Hot reload enabled
+- Port: 3001
+- Mounts source code for live editing
+- Profile: `dev`
+
+### api-docs (API Documentation)
+- Swagger UI for API documentation
+- Port: 3002
+- Profile: `docs`
+
+### monitoring stack
+- Prometheus (port 9090) and Grafana (port 3003)
+- Profile: `monitoring`
+
+## Profiles
+
+Use profiles to enable optional services:
+
+```bash
+# Development only
+docker compose --profile dev up
+
+# With API documentation
+docker compose --profile docs up
+
+# With monitoring
+docker compose --profile monitoring up
+
+# Everything
+docker compose --profile dev --profile docs --profile monitoring up
+```
+
+## Environment Variables
+
+Create a `.env` file for custom configuration:
+
+```env
+# JWT Configuration
+JWT_SECRET=your-secret-key-here
+
+# API Configuration
+API_ENABLED=true
+API_PREFIX=/api/v1
+API_RATE_LIMIT=100
+API_RATE_WINDOW=15m
+
+# Development
+HTTP_ALLOWED=false
+ALLOW_UNAUTHENTICATED=false
+
+# Timezone
+TZ=America/New_York
+
+# Monitoring
+GRAFANA_PASSWORD=secure-password
+```
+
+## Development Workflow
+
+1. **Start development environment**:
+   ```bash
+   docker compose --profile dev up convertx-dev
+   ```
+
+2. **Make code changes**: Edit files in `src/` - they'll auto-reload
+
+3. **Test production build**:
+   ```bash
+   docker compose up --build convertx
+   ```
+
+4. **View logs**:
+   ```bash
+   docker compose logs -f convertx-dev
+   ```
+
+## Building Images
+
+```bash
+# Build all images
+docker compose build
+
+# Build specific service
+docker compose build convertx
+
+# Build with no cache
+docker compose build --no-cache
+```
+
+## Data Persistence
+
+- Application data: `./data` directory (mounted to `/app/data`)
+- Prometheus data: `prometheus_data` volume
+- Grafana data: `grafana_data` volume
+
+## Networking
+
+All services are on the `convertx-network` by default. To expose services to other containers:
+
+```yaml
+external_service:
+  networks:
+    - convertx-network
+  external_links:
+    - convertx
+```
+
+## Troubleshooting
+
+1. **Port conflicts**: Change ports in docker-compose.yml if needed
+2. **Permission issues**: Ensure `./data` directory has correct permissions
+3. **Build failures**: Check Dockerfile and ensure all dependencies are available
+4. **Hot reload not working**: Verify volume mounts and file permissions
+
+## Production Deployment
+
+For production, consider:
+
+1. Use specific image tags instead of `latest`
+2. Set strong JWT_SECRET
+3. Disable HTTP_ALLOWED and ALLOW_UNAUTHENTICATED
+4. Configure proper backup for data directory
+5. Set up monitoring with the monitoring profile
+6. Use external database for scale