Five files assigned process.env.GSTACK_HOME at module scope. Shard
processes evaluate sibling modules before running their tests, so the
assignment leaked into every other file in the shard — the damage was
already visible in defensive workarounds (relink.test.ts:28 'fresh
install test saw a neighbor's skill_prefix'; cdp-e2e's own comment
documents a sibling's temp dir baked into artifacts).
Pattern: save original, assign in beforeAll, restore in afterAll
(cdp-e2e already restored but still assigned at load — its window now
matches the others). GSTACK_TELEMETRY_OFF and GSTACK_PROJECT_SLUG get
the same treatment where they rode along. Victim files' defenses stay
in place (cheap insurance).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>