run the root check warn-only on hyperhive's own containers, per unit, not on the container@ template

nix/host-modules/swarm-builder.nix

@@ -52,6 +52,8 @@ let
   # containers' forwarders all the same.
   forwarderTelemetryPort = 8892;
 
+  rootfsCheck = import ./lib/container-rootfs-check.nix { inherit config; };
+
   # The daemon reaches authelia, the store and the queue by name over TLS, and
   # `git` reaches the forge; in self-signed mode their leaves chain to the hive
   # CA.
@@ -165,6 +167,7 @@ in
     # the unit does not exist.
     systemd.services."container@${machine}" = lib.mkMerge [
       caTrust.containerOrdering
+      (rootfsCheck.warnOnly machine)
       {
         after = [ "swarm-bao-pki.service" ];
         wants = [ "swarm-bao-pki.service" ];