The push-audit-events initiator test injects a request with
:app.http/auth-key-id via :app.http/request metadata. prepare-rpc-params
always replaced that metadata with a fresh DummyRequest, so the key id
was lost and the initiator fell back to "app".
Honor a caller-supplied request map, merging body params into its
:params, and keep the dummy request only for non-map IRequest stubs
(reify requests used by the audit tests, which cannot be assoc'd).
Add focused regression tests for the three cases and document the
helper contract in the backend testing memory.
AI-assisted-by: deepseek-v4.1-flash
Extract the backend Testing section from backend/core into a dedicated
backend/testing memory, following the pattern of common, frontend, and
exporter. Update the testing skill and root testing memory to point at
the new location, and add exporter/testing to the skill's required
reading list.
AI-assisted-by: deepseek-v4-flash
