Full API spec covering all 16 subsystems: Core container, primitives
(Option/Options/Result), service system, IPC (ACTION/QUERY/PERFORM),
Config, Data, Drive, Fs, CLI, error handling, logging, strings, paths,
utils, locks, ServiceRuntime.
An agent can write a Core service from this document alone.
Co-Authored-By: Virgil <virgil@lethean.io>