Agents are handed `http://hive-collector.<swarm domain>:<port>` as their
otel endpoint instead of `http://<bridge IP>:<port>`. Every hive running
its collector contributes the name to `gateway.localNames`, so its own
dnsmasq answers it with its bridge IP, the way the queue's name already
works. The rendered meta flake then carries no hive-specific address,
which a swarm-level render needs (#4857, operator ruling 100744: "b").
hive-c0re's own exporter keeps the bridge address: on the host the name
may resolve to loopback through `gateway.localHostsEntry`, where the
receiver does not listen.
The name sits under the swarm domain and starts with `hive`, a fragment
no hive name may contain, so no hive's default domain can take it.
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