Core reaches the mockmed break-it fixture through qualification_oracle_gate #1876

The import-boundary contract in #1874 (packages/flow/import_layers.json) records one transitive exception. Core reaches mockmed.fault_server, the break-it test fixture, through receipt > repair > agent > admit_pipeline > qualification_proposal > qualification_oracle_gate.

Fix: move the fixture dependency out of the runtime path. qualification_oracle_gate should take the fault server as an injected dependency, or import it lazily only in the qualification CLI or test entry points. Then delete the exception from import_layers.json. The contract test must pass with no exceptions.

Don't weaken the qualification gate's behaviour.