Streamlined API client initialization within the NewApi function by directly invoking the client creation. Additionally, removed custom type declarations and constants in model/product.go, replacing them with simpler string types to reduce complexity.
This commit introduces new API and client modules that provide functionality for managing categories and products. It includes the creation of `.gitignore`, necessary data models, API endpoints, and client authentication using go-resty. This forms the foundation for further enhancements to the category and product management features.