Define multiline reStructuredText docstrings and item-level documentation for dataclasses, Pydantic models, and Protocols. Align agent instructions, review guidance, and development documentation.
Validation: document links, Python example syntax, docstring format, and diff checks passed. The unchanged text-only architecture documentation test passed under isolated pytest with temporary CONFIG_DIR and no application bootstrap. Normal bootstrap remains unverified because the local environment lacks moviepilot_rust; installed uv also predates the project configuration format. No product code changed.