The publisher was a oneshot with RemainAfterExit=true, started only through
`wantedBy = container@hive-forge.service`. Once it had run it stayed
`active (exited)`, so a later container start made its start a no-op: a token
re-minted without a host reboot or a unit change never reached the store.
- RemainAfterExit is dropped, so each start runs the script again.
- systemd.paths.swarm-bao-forge-publisher watches the token file in the
container (PathChanged) and starts the publisher when the mint writes it,
the same shape as swarm-secret-publish's path unit.
- The code comment, secrets.md and credentials.md now name both triggers;
forge-placement pins the missing RemainAfterExit and the path unit.
Refs #4998
2d2d7529fc