SubmitQueue service layout:

• gateway/ — Gateway service: entry point for Ping, Land, Cancel, request-summary, request-history, and queue-listing RPCs. It also consumes request-log events and maintains the public request projections. gateway/core/request materializes those logs; gateway/extension/storage is the aggregate, MySQL implementation, and schema only the gateway resolves.
• orchestrator/ — Orchestrator service: coordinates validation, dependency analysis, speculation, builds, landing, cancellation, conclusion, hooks, and DLQ reconciliation. orchestrator/core/request publishes and terminates requests, orchestrator/core/batch moves batches, and orchestrator/extension/storage is the aggregate, MySQL implementation, and schema only the orchestrator resolves.
• extension/ — SubmitQueue-specific extension contracts and implementations, including the shared storage contracts, queue configuration, change providers, validation, conflict analysis, speculation, and build runners. Service aggregates and MySQL backends live under the service that resolves them.
• entity/ — SubmitQueue-specific domain entities.
• client/ — Gateway client used by command-line tools and the demo.
• core/ — Infrastructure shared by the gateway and the orchestrator: change-set resolution (changeset), internal queue contracts (messagequeue), and topic keys (topickey).

Cross-domain building blocks live outside this directory: shared entities in platform/base/, shared extensions in platform/extension/, and cross-domain infrastructure such as the consumer framework in platform/.