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

frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginSteps.ts

@@ -0,0 +1,42 @@
+// The claude login dialog's steps, kept out of the component so `npm test`
+// runs them. The routes are swarm-controller's `claude_login` module.
+import type { ProblemDetails } from "@hive/shared/api-error.js";
+
+export type LoginStep =
+  | { step: "starting" }
+  | { step: "code"; url: string }
+  | { step: "submitting"; url: string }
+  | { step: "stored" }
+  | { step: "failed"; problem: ProblemDetails };
+
+export function claudeLoginPath(agent: string, code = false): string {
+  return `/api/agents/${encodeURIComponent(agent)}/claude-login${code ? "/code" : ""}`;
+}
+
+// The step after the start answered: its URL, or why there is none.
+export function afterStart(
+  answer: { url: string } | { problem: ProblemDetails },
+): LoginStep {
+  return "url" in answer
+    ? { step: "code", url: answer.url }
+    : { step: "failed", problem: answer.problem };
+}
+
+// The step after the code was posted. The minter ends the login on a
+// refused code, so the next attempt is a fresh start.
+export function afterCode(problem: ProblemDetails | null): LoginStep {
+  return problem === null ? { step: "stored" } : { step: "failed", problem };
+}
+
+// Whether closing the dialog leaves a login running that should be
+// stopped.
+export function leavesLoginRunning(s: LoginStep): boolean {
+  return s.step === "code";
+}
+
+// What the code form may submit: the pasted code without surrounding
+// whitespace, or nothing.
+export function pastedCode(raw: string): string | null {
+  const code = raw.trim();
+  return code === "" ? null : code;
+}