Linux-only START imminent, ZR2WI626 applied BEFORE launch: purge every inherited OWL_*/SPT_* name from both driver and producer env; allow only SPT_TEST_EPHEMERAL_ADVISORY_PORTS. environment.json captures ALL env key names, no values, before/after each producer and refuses extra OWL/SPT names. Own temporary sandbox path retained outside producer env (TEMP/TMP/TMPDIR unchanged); prior custom SPT_ATTACH_* bounds removed as ruled. Same b8482445 tree, warm target, unchanged A/B commands. Anchored reap/admission precede cargo. Windows remains yours. Attempt2 retained as-is with adjacent QUALIFICATION.json.