The harness now reads swarm/agents/<agent>/queue from the store itself,
under the agent's own store certificate, and holds it in memory only.
It reads once before the first connect and again on every reconnect
attempt (async-nats `ConnectOptions::with_auth_callback`), so an agent
whose secret was re-minted reconnects with the new value instead of
being refused until the container restarts.
hive-agent-queue-credential.service, the /run file it wrote, and
HIVE_AGENT_QUEUE_AGENT_SECRET_FILE are gone; queue-identity.nix now
hands hive-agent.service the store address, its certificate paths and
the agent name.
A failed or empty read before the first connect still falls back to
the hive's shared client. Each read is bounded by a 10s timeout, and
retries wait out the existing reconnect backoff (500ms doubling, capped
at 60s).
Closes#4783
`script-test-agent-bao-fetch` executes the rendered `ExecStart` of
`hive-agent-forge-token` and `hive-agent-queue-credential` under
`umask 0377`, with a stub `bao` first on the unit's own PATH. It covers
every error branch, the happy path, forge rotation/unchanged, and 0400
files already in place: the redirect failure #4736 fixed, whose live
symptom was `bao.err: Permission denied` reported as a refused
certificate. The TLS-alert fixture is the `unknown certificate
authority` error h-atlas's identity check got from the store.
#4736 claimed this test but never committed it; the two module-eval
suites for these units only evaluate the config.
Closes#4748