Deleted client/credential.go and moved the Credentials struct to the api package for better modularity. Enhanced type safety in api by checking type assertions and added detailed comments in model structs.
Implemented `GetProductByArticle` to fetch product details by article. Added `GetRemainsAndPlanresidues` to obtain inventory balances for categories. These enhancements improve the API's capability to manage product and inventory information.
Introduced a new method `GetTreeCategories` to provide a hierarchical structure for categories. Fixed typos in variable names and integrated utility functions for converting flat lists to nested dictionaries and vice versa. Added `TreeCategories` model for representing nested category structures.
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.