SubmitQueue service layout:

• gateway/ — Gateway service: entry point for land requests (Ping, Land, Cancel RPCs).
• orchestrator/ — Orchestrator service: coordinates the land pipeline (batch, score, build, merge, conclude, ...).
• extension/ — SubmitQueue-specific extension implementations (storage, counter, changestore, mergechecker, pusher, scorer, conflict, queueconfig, buildrunner, ...).
• entity/ — SubmitQueue-specific domain entities.
• core/ — Infrastructure shared across SubmitQueue's own services (gateway and orchestrator): the queue consumer framework and the request lifecycle. The SubmitQueue-scoped analogue of the repo-level core/.

Cross-domain building blocks live outside this directory: shared entities in entity/, shared extensions in extension/, and cross-domain infrastructure in the top-level core/.