Module federation 

Federation contracts (interfaces only; no network implementation yet).

What is already in place to keep federation possible:

• identifiers carry their origin (crate::id::RecordId),
• relations may point at remote records and carry a target_locator,
• bundles are self-verifying and imports enforce an origin policy (crate::interchange::ImportPolicy),
• imported events keep their original ids, so re-sync is idempotent.

Open questions (discovery, signatures, key rotation, replay protection, tombstones, cross-domain moderation) are listed in docs/federation.md.

Traits

RemoteSource

Something that can fetch records published by another origin.