API documentation source structure

[rsgalloway]

Add docs/api/ folder for generated API documentation (MkDocs / Sphinx)

Description
Prepare the repository for generated API documentation by adding a dedicated source directory.

Create a new folder:

docs/api/

This directory will contain source files only (not built artifacts) for generating API documentation using MkDocs or Sphinx.

Scope

• Add the directory and an initial placeholder (e.g. index.md or conf.py)
• No requirement yet to fully wire up CI or publishing

Acceptance Criteria

• docs/api/ directory exists in the repo
• Contains at least one source file suitable for MkDocs or Sphinx

Notes

• Generated docs will be published externally (e.g. GitHub Pages or ReadTheDocs)
• This issue is intentionally limited to structure and scaffolding