Federation goes per-account

Federation is now scoped per account rather than per node. Each account acts as its own peer, with its federation data held in that account’s own database, and a single code path governs how nodes exchange published content. This keeps the isolation boundary consistent: the same database-per-account model that separates data now also separates federation.

In practice you can run one private authoring node alongside any number of public delivery nodes and keep them in sync without a shared, node-wide configuration. Data residency and sovereignty stay the default, and adding or removing a peer no longer touches global node settings.