Overloading NODE_ENV='test' to silently disable rate limiting layered a
second meaning onto an env that already gates the test-only seed-peer
route. A dedicated DISABLE_RATE_LIMITS env (envBool semantics, matching
DISABLE_FEDERATION_WORKERS) makes intent explicit, defaults off in
production, and leaves room for tests that need to assert real rate-limit
behaviour to opt back in by simply not setting the var.