swarm-authelia: run the secret publisher and a journal forwarder inside the container

swarm-secret-publish and its path unit now run inside authelia's container,
beside the mint, and read each client secret at the path authelia writes it.
The host unit and host path unit, which read the secrets through the
container's root on the host, are gone, and so is
deploy.authelia.hostClientSecretDir, which only they read. The publisher keeps
its store identity, the secret-publisher leaf. The host hands the leaf and the
store's CA into the container as nspawn system credentials, and the unit loads
them; where this host mints the leaf, the container waits for swarm-bao-pki.
Authelia does not wait for the publisher, which retries every 30 seconds while
the store is down.

The container also runs the journal forwarder the other service containers
run, pushing to a receiver of its own on the swarm collector (serviceProducers
swarm-authelia) as a new machine OIDC client (swarm.authelia.otel.clientId)
that authelia registers for itself and the publisher carries to the store. The
fetch unit reads it back under the publisher's leaf, also handed to it as a
system credential, so the swarm-secret-publisher policy gains read on that one
leaf; its stanza keeps create and update, which the exact path would otherwise
take from the services/* prefix. Without the leaf the forwarder is off.

The container drops --link-journal=host, and the host collector stops reading
it. The services' "nothing at <path>" errors name the publisher in authelia's
container.

nix/host-modules/swarm-grafana.nix

@@ -278,7 +278,7 @@ let
     "/var/lib/grafana-metrics/bearer"
   ];
 
-  # Where the publisher on authelia's host leaves this client's secret. A
+  # Where the publisher in authelia's container leaves this client's secret. A
   # swarm service's client is registered once for the whole swarm, so its
   # secret is one value and not one per hive. Both ends compose this from the
   # same swarm-wide client id, so a rename cannot leave one of them behind.
@@ -649,11 +649,11 @@ in
     ++ map (p: "r ${p}") legacyHostSecretPaths;
 
     # THE delivery unit — one route, in every deployment. The secret authelia
-    # minted arrives out of the swarm secret store, which the publisher on
-    # authelia's host wrote it into, and that is true whether authelia is a
-    # network away or in the container next door.
+    # minted arrives out of the swarm secret store, which the publisher in
+    # authelia's container wrote it into, and that is true whether authelia is
+    # a network away or in the container next door.
     #
-    # 🩸 No second unit copies the plaintext out of authelia's host tree
+    # 🩸 No second unit copies the plaintext out of authelia's tree
     # where the two are co-located. The store exists so a host holds ONE
     # out-of-band secret — its client certificate — and reads everything else
     # with it, so skipping the store when the producer is local would buy a
@@ -667,8 +667,9 @@ in
     # that degrades QUIETLY, since no retry turns "no value there" into a value.
     #
     # ⚠️ An ABSENT secret is "not published yet", not a fault of this host's.
-    # The publisher runs on the authelia host and authelia mints on its first
-    # boot, so early in a swarm's life there is legitimately nothing to read.
+    # The publisher runs in authelia's container and authelia mints on its
+    # first boot, so early in a swarm's life there is legitimately nothing to
+    # read.
     # Nothing here writes a stand-in: there is no such thing as a locally valid
     # OIDC client secret, and a placeholder would turn a Grafana that cannot
     # log anyone in into one whose token exchange is refused.