hive-forge: the controller-token mint writes straight to the store, and the on-disk token goes

`forgejo-swarm-controller-account`, in the forge's container, now puts
the swarm-controller's forge token into the swarm secret store itself,
under the forge publisher's leaf. The container already receives that
leaf as nspawn system credentials for its journal forwarder; the mint
loads the same three. The token reaches bao on stdin (`value=-`) and
the forge's API through a header file, never as an argument, and never
touches disk.

The mint's guard is a marker holding the published token's name, at
/var/lib/forgejo/swarm-controller-token-name, written last: after the
put, and after every other `swarm-controller-boot-*` token of the
account is revoked through forgejo's admin API, authenticated as the
new token. So a put that failed, or a marker lost while the store kept
an older token, leaves no live token behind once a mint completes. The
mint logs in to the store and checks that the account is a site admin
before it mints, so a store that is down or an account the admin API
would refuse mints nothing on each retry. Failures retry under
store-retry; forgejo does not wait for the mint. No bao read and no
grant change: the forge publisher keeps create/update on the token.

Removed: the host's `swarm-bao-forge-publisher` service and path unit,
which read the token file through the container's root, and their
entries in the store and policy ordering glue. The forge publisher's
policy unit stays; `swarm-bao-forge-oidc` still uses the leaf.

On deploy, an existing forge host has no marker, so the mint runs once:
it mints a new token, publishes it, revokes the old one, and deletes
the old /var/lib/forgejo/swarm-controller-token. The controller's next
forge call gets a 401, re-reads the store and carries on.

nix/module-eval/swarm-services-switch.nix

@@ -819,7 +819,6 @@ let
           ];
           readers = [
             "swarm-bao-forge-oidc"
-            "swarm-bao-forge-publisher"
             "swarm-bao-matrix-oidc"
             "swarm-bao-hive-otel-oidc"
             "swarm-bao-grafana-oidc"
@@ -848,7 +847,7 @@ let
             !(lib.any (n: lib.elem n (s.after ++ s.wants ++ s.requires)) storeUnits);
         in
         lib.all waits readers
-        && lib.length readersElsewhere == 8
+        && lib.length readersElsewhere == 7
         && lib.all namesNoStoreUnit readersElsewhere
         && !(lib.any (u: storeOnlyNoHive.systemd.services ? ${u}) readers);
     }