The full python3 tools/check.py suite passed. The new production-body test executes failure-only eligibility, menu/dialog focus preservation, native pause fallback, exact error text, Back routing, one local exit request, recovered/stale mode guards and listener removal. Existing loading-overlay lifecycle checks pass.

The final isolated Workbench fixture completed six native assertions:

The real failed-start menu was focused, with both buttons bound, the exact error displayed and the native black loading placeholder hidden.
Clicking the actual pause-button invoker opened the native pause menu with focus and no black overlay, then returned to the failed round.
Calling the production Back handler opened native pause again and restored failure-menu focus after closing it.
Clicking the actual Return-to-main-menu button caused native gameplay end. The menu's input/button listeners and references were cleaned up within five seconds of that click; the log also shows the main-menu world and welcome UI.

The fixture forces a preparation failure in its private source copy. It invokes real button callbacks and the real Back handler; it does not claim physical mouse/keyboard/controller input, a multiplayer disconnect or pixel-level layout verification. Production code uses vanilla's local gameplay-end transition. No mission-state, admission or server-command workaround is involved.

The strict native reporter exits 1: the raw log includes the intentional preparation error, resource/world errors, and two SCR_FilterCategory constructor errors while opening the main-menu UI. These are retained in the unfiltered report; the exit and cleanup assertions completed afterward. The private prefix cleanup and unchanged source/dependency hashes were verified. This is not a claim of an error-free engine run.

During development, native compilation caught an override parameter-name mismatch (corrected to tDelta). The older generic startup-failure fixture reached the interactive screen but failed an unrelated expected-faction/stock assertion. The focused fixture then needed its intended startup error allowed by the runner, and its cleanup observation adjusted for menu closure after game-end notification. The final retained run exercises the current production bytes.

Reproduce with an unused alphanumeric suffix:

python3 tests/test_preparation_failure_menu.py
python3 tests/test_preparation_status.py
python3 docs/evidence/preparation-exit-2026-10-25/isolated-runner.py next01

The runner freezes production sources and injects native-fixture.c only into that disposable copy. It uses a private profile/prefix and no live mission.