Adds an explicit override for the federation transport URL returned by
getOurOrigin(). When unset, behaviour is unchanged (https://${DOMAIN} ->
http://localhost:${PORT} dev fallback). Intended for reverse-proxy /
dev-without-TLS deployments where the public origin must be advertised
explicitly (typically http://...) and differs from the bare DOMAIN
value used for federated identity.
Wired via config.publicOrigin (envOptional('PUBLIC_ORIGIN')) so the
override flows through the existing config layer rather than scattering
process.env reads. Trailing slash is stripped for symmetry with
peer.origin storage.
docs/systems/federation.md gets a "Public Origin Override" subsection
under §14 Background Workers documenting the resolution order.
Jannis Braun
d55e85d2c5