nix: run the review classifier in a container of its own when a host enables it

deploy.review-classifier.enable (off by default, not derived from
allSwarmServices) puts swarm-review-classifier in its own network
namespace on the bridge, with claude-code and the daemon. A host unit
copies the classifier's store leaf into the container; the daemon reads
its queue client secret and the API key from the store with it.

- glue-bao-tls mints the review-classifier leaf; swarm-bao writes the
  swarm-review-classifier role, reading exactly the API key path and the
  classifier's queue client secret; swarm.nix reserves its CN.
- glue-review-classifier-oidc-client registers the machine client where
  authelia runs, and the publisher carries its secret to the store.
- swarm-nats passes the client id to the responder as
  --review-classifier-client.
- Where the host runs a hive-tier collector, claude exports its metrics
  there; the daemon adds the repo and the PR to the resource attributes.
- module-eval: the new grant and leaf (bao-grants, now sixteen granting
  units), the container's presence and its unit (core-toggle), and the
  client registration and publishing (secret-publisher).

nix/host-modules/deploy.nix

@@ -642,6 +642,23 @@ in
       '';
     };
 
+    review-classifier.enable = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      example = true;
+      description = ''
+        Run the review classifier in a `swarm-review-classifier` container on
+        this host. It answers the swarm UI's review try-outs with `claude` on
+        the Anthropic API key the operator writes to the secret store at
+        `secret/swarm/services/review-classifier/anthropic-api-key`, field
+        `api_key`.
+
+        Not derived from
+        {option}`services.hyperhive.deploy.allSwarmServices`: every run spends
+        money on that key, so running one is a decision of its own.
+      '';
+    };
+
     hive-controller.enable = lib.mkOption {
       type = lib.types.bool;
       default = false;