API workrkflow.txt

Title: Document end-to-end API workflow and usage

Description:
While individual endpoints are documented, there is no single guide explaining how the API is used from start to finish. This issue adds a clear, step-by-step workflow description for typical usage scenarios.

Tasks:

Describe the donation flow from request to confirmation

Explain required headers, authentication, and metadata

Provide example request/response sequences

Add common failure scenarios and how to handle them

Acceptance Criteria:

A reader can understand how to use the API without reading the code

Examples are accurate and up to date

Documentation lives in README or /docs