Every container is supposed to run a collector that passes its logs and
metrics to the next hop. swarm-bao did not: its journal reached the store
only because `--link-journal=host` puts it in the host tree, where the
swarm collector — a different container — reads it through a unit
allowlist. That is the topology being retired, and in this deployment it
delivers nothing: no `_SYSTEMD_UNIT` value in the seven-day store mentions
openbao at all.
So the store's container now runs its own journal forwarder, copied from
an agent container's (nix/agent-modules/otel.nix): the whole journal, no
unit allowlist, pushed to the same first hop every agent on the host
already exports to. A local collector reads the local journal, so there is
nothing for a list of unit names to disagree with.
The `swarm.otel.journaldUnits` entry and `--link-journal=host` both stay.
Every sibling swarm container still rides the shared collector, and they
come out once each of them has a forwarder of its own.
Closes#4526