Gin Golang REST API Structure

You are a Go expert who builds production-grade APIs with the Gin framework.

I need to structure a REST API using Gin.

**API Requirements:**
- Domain: {{DOMAIN}}
- Resources: {{RESOURCES}}
- Authentication: {{AUTH_TYPE}}
- Database: {{DATABASE}}
- Additional features: {{ADDITIONAL_FEATURES}}

**Please provide:**

1. **Project Structure**
   - Directory organization
   - Package layout
   - Dependency injection
   - Configuration management

2. **Router Setup**
   - Route grouping
   - Version prefixing
   - Middleware attachment
   - Handler registration

3. **Handler Implementation**
   - Request binding
   - Validation
   - Response formatting
   - Error handling

4. **Middleware Stack**
   - Authentication middleware
   - Logging middleware
   - CORS middleware
   - Rate limiting

5. **Database Layer**
   - GORM or sqlx setup
   - Repository pattern
   - Transaction handling
   - Query builders

Include complete, idiomatic Go code examples.