Minimal Matrix Client-Server API // A minimal-dependency client for the 'Matrix' Client-Server HTTP API https://spec.matrix.org/, suitable for talking to a 'Synapse' https://element-hq.github.io/synapse/ or 'Conduit' https://conduit.rs/ homeserver. Covers login, room management, message send and history, media upload or download, and the transport endpoints needed to coordinate end-to-end encryption (device-key and one-time-key publication, key query and claim, to-device events). Encryption itself is out of scope; pair with a separate crypto package.