read_with_startup_retry retries the first read of a client secret through a store that is restarting. Nothing in swarm-queue-client calls it; its only callers are the four binaries that read the secret (swarm-builder, swarm-claude-login, swarm-controller, swarm-review-classifier), and they already depend on swarm-secret-client. It sits beside stored_secret, which moved there in #5538. swarm-queue-client drops its backon dependency and the tokio test-util dev-dependency that only these tests used.
