mocking-strategy-roster

Use when an agent must mock a downstream HTTP/event dependency for an integration test and needs to know WHICH mocking strategy and stack adapter to use. Resolves the mocking strategy (Microcks by default, overridable to an in-process library) and the stack, then points to the concrete mocking-<strategy>-<stack> adapter. Loaded by the mock-integration-worker. No agent hardcodes a mocking approach — it resolves it here.