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-secret-client/src/lib.rs

@@ -6,8 +6,9 @@
 //! deployment's environment into a logged-in client ([`client`]), and, per kind
 //! of secret, the path it lives at together with the fields it holds
 //! ([`matrix`], [`queue`], [`mtls`], [`forge`], [`github`], [`acp`], [`ci`],
-//! [`review_classifier`], [`builder`]). Each of those is a thing the controller
-//! and a hive must say identically, so it is said once here.
+//! [`review_classifier`], [`builder`], [`claude_login`]). Each of those is a
+//! thing the controller and a hive must say identically, so it is said once
+//! here.
 //!
 //! [`policy`] is the same kind of agreement seen from the other side: which of
 //! those paths a given principal's own token may read — a hive's, and an
@@ -26,6 +27,7 @@
 pub mod acp;
 pub mod builder;
 pub mod ci;
+pub mod claude_login;
 pub mod client;
 pub mod forge;
 pub mod github;