The unihost API path delegates to engine.deployer.deploy(), which now
writes both decnet-state.json (existing) and the fleet_deckies DB
table (added in 646aeec). Comment makes the single-sink design
explicit so future maintainers don't add a parallel save_state /
upsert_fleet_decky call here.
No behavioral change — every fleet-creation path on every host (CLI
deploy, this unihost API path, and per-worker SWARM agent deploys)
already routes through the engine.deployer single sink.