Ports and adapters, dependencies inward

• Context: use cases that shell out or speak HTTP cannot be tested without the tools, and every new tool edits them.
• Decision: the domain imports only itself; the core imports the domain, its ports and the meter; adapters implement the ports; one composition root picks them.
• Consequence: the core runs in tests with no network and no process; a new agent, manager or sink is an adapter and a registry entry.
• Enforced by: TestArchitecture, TestCoreImports, TestDomainImports, TestDaemonImports, TestReadModelImports. See Layers.