Why: Direct artifact registration trusted filename extensions, the shared renderer parity test used a reduced fixture, and migration comparison omitted canonical list/task/rule/alignment properties plus their Word presentation.
Evidence: go test -count=1 ./...; go test -race ./internal/docgen ./internal/tools ./internal/runmgr; go vet ./...; go build ./...; PYTHONPATH=. python3 -m unittest tests.test_housestyle; git diff --check.
Impact: Reject renamed WordprocessingML packages while preserving non-Word artifacts, pin the reviewed renderer semantics, and report canonical and DOCX presentation regressions as accidental differences.
Refs: Task 10; /tmp/task10-backend-final-review-last.md