swarm UI: log an agent into claude from its card; the credentials go to bao and the agent picks them up

A new swarm service, `swarm-claude-login`, in its own container on the host
that sets `deploy.claude-login.enable` (defaulted on by `allSwarmServices`
where the host has the minter's store leaf, like the review classifier).

- swarm-ui: an agent card showing "login needed" gets a "log in" button.
  Its dialog starts the login, shows the URL claude printed, and takes the
  pasted code.
- swarm-controller: `POST/DELETE /api/agents/{name}/claude-login` and
  `POST /api/agents/{name}/claude-login/code`, behind the swarm UI's
  authelia-gated `/api/`, relay the steps to the minter as requests on
  `$SWARM.claude-login.request`.
- swarm-claude-login: runs `claude auth login` over piped stdio with HOME
  and CLAUDE_CONFIG_DIR in a per-login scratch dir, scrapes the first
  https URL, writes the code to stdin, and stores the `.credentials.json`
  at `swarm/agents/<agent>/claude-credentials` with a KV v2 write, a new
  version over any earlier one. The scratch dir goes on every exit path; a
  login waits 15 minutes for its code.
- hive-agent: while parked in `wait_for_login`, reads that leaf every 30 s
  under the agent's own cert and installs it only when its KV version is
  newer than the one recorded in `<harness>/claude-credentials-version`.
  An equal or older version is never put back, because claude rotates the
  refresh token and the stored copy is stale after the first refresh.
- swarm-secret-client: `claude_login` paths and `SecretStore::read_versioned`.
- Credentials: a `claude-login` store leaf minted by glue-bao-tls, a
  `swarm-claude-login` policy (create/update on
  `swarm/agents/+/claude-credentials`, read on its own queue client
  secret), an authelia machine client, and a `--claude-login-client`
  grant in the queue's auth-callout responder. The unit runs as a static
  system user.

The hive's own web-UI login is unchanged.

Refs #5268

swarm-nats-auth/src/policy.rs

@@ -51,6 +51,7 @@ pub struct Policy {
     agent_token_subjects: Vec<String>,
     review_classifiers: Vec<String>,
     builders: Vec<String>,
+    claude_logins: Vec<String>,
 }
 
 /// Placeholder replaced with the hive's own name in `extra_hive_subjects`.
@@ -122,6 +123,7 @@ impl Policy {
             agent_token_subjects: Vec::new(),
             review_classifiers: Vec::new(),
             builders: Vec::new(),
+            claude_logins: Vec::new(),
         })
     }
 
@@ -157,6 +159,13 @@ impl Policy {
         self
     }
 
+    /// Set the client ids that answer the claude login minter's requests.
+    #[must_use]
+    pub fn with_claude_logins(mut self, clients: Vec<String>) -> Self {
+        self.claude_logins = clients;
+        self
+    }
+
     /// The permissions for an agent whose own credential was verified, or
     /// `None` when none are configured.
     ///
@@ -229,6 +238,9 @@ impl Policy {
         if self.builders.iter().any(|c| c == client_id) {
             return Some(Self::builder_permissions(client_id));
         }
+        if self.claude_logins.iter().any(|c| c == client_id) {
+            return Some(Self::claude_login_permissions(client_id));
+        }
         None
     }
 
@@ -263,6 +275,20 @@ impl Policy {
         }
     }
 
+    /// What the claude login minter may do: hear login steps and answer each
+    /// on its reply subject. Its publish list is its own inbox, for
+    /// [`Self::review_classifier_permissions`]' reason.
+    fn claude_login_permissions(client_id: &str) -> Permissions {
+        Permissions {
+            publish: vec![Self::inbox(client_id)],
+            subscribe: Some(vec![
+                swarm_queue_client::claude_login::SUBJECT.to_owned(),
+                Self::inbox(client_id),
+            ]),
+            responses: Some(swarm_queue_client::claude_login::REPLY_DEADLINE),
+        }
+    }
+
     /// What a hive may subscribe to: the two events the controller sends it,
     /// and its own reply inbox.
     ///
@@ -603,6 +629,8 @@ impl Policy {
             swarm_queue_client::review_classifier::SUBJECT.to_owned(),
             // A build of an agent config, sent as a request the same way.
             swarm_queue_client::builder::SUBJECT.to_owned(),
+            // An operator's claude login step, sent as a request the same way.
+            swarm_queue_client::claude_login::SUBJECT.to_owned(),
             // The wanted-state buckets — one per hive, all created and written
             // by this single client.
             //
@@ -1402,6 +1430,63 @@ mod tests {
         }
     }
 
+    const CLAUDE_LOGIN: &str = "swarm-claude-login";
+
+    #[test]
+    fn the_claude_login_minter_hears_its_subject_and_inbox_only_and_answers_by_reply() {
+        use swarm_queue_client::claude_login::{REPLY_DEADLINE, SUBJECT};
+        use swarm_queue_client::client_inbox_prefix;
+
+        let p = policy()
+            .with_claude_logins(vec![CLAUDE_LOGIN.to_owned()])
+            .permissions(CLAUDE_LOGIN)
+            .expect("a configured minter is admitted");
+        let inbox = client_inbox_prefix(CLAUDE_LOGIN);
+        assert!(may_subscribe(&p, SUBJECT));
+        assert!(may_subscribe(&p, &reply(&inbox)));
+        for refused in [
+            ">".to_owned(),
+            "$SWARM.>".to_owned(),
+            swarm_queue_client::builder::SUBJECT.to_owned(),
+            reply(&client_inbox_prefix("swarm-controller")),
+        ] {
+            assert!(
+                !may_subscribe(&p, &refused),
+                "the minter may subscribe to {refused}"
+            );
+        }
+        assert_eq!(p.publish, vec![format!("{inbox}.>")]);
+        assert_eq!(p.responses, Some(REPLY_DEADLINE));
+        // The minter's id is nothing until it is configured.
+        assert_eq!(policy().permissions(CLAUDE_LOGIN), None);
+    }
+
+    #[test]
+    fn only_the_reader_may_send_a_login_step() {
+        use swarm_queue_client::claude_login::SUBJECT;
+
+        let p = with_classifier()
+            .with_builders(vec![BUILDER.to_owned()])
+            .with_claude_logins(vec![CLAUDE_LOGIN.to_owned()]);
+        let reader = p.permissions("swarm-controller").expect("the reader");
+        assert!(reader.publish.iter().any(|g| covers(g, SUBJECT)));
+        for (who, grant) in [
+            ("a hive", p.permissions("hive-alpha").expect("a hive")),
+            ("the minter", p.permissions(CLAUDE_LOGIN).expect("admitted")),
+            ("the builder", p.permissions(BUILDER).expect("admitted")),
+            (
+                "the classifier",
+                p.permissions(CLASSIFIER).expect("admitted"),
+            ),
+        ] {
+            assert!(
+                !grant.publish.iter().any(|g| covers(g, SUBJECT)),
+                "{who} may send a login step: {:?}",
+                grant.publish
+            );
+        }
+    }
+
     #[test]
     fn the_prefix_alone_names_no_hive() {
         // `hive-` would otherwise produce `$KV.hive-status.`, a subject nobody