Parent tracker: #66. Follow-up from #432.
After b4ddf3056, the strict native test/cli/install/bunx.test.ts run reports 32 passed, 1 platform skip, and 1 failure. The sole failure is should work for github repository: the live github:piuccio/cowsay checkout now renders Usage: <runtime executable> (Usage: home-release-fast under Home). The pinned Bun 1.4.0 control fails the identical copied assertion with Usage: bun, while both runtimes pass the committish GitHub case.
This is moving external fixture drift, not a Home runtime divergence. Do not falsify process.argv, weaken the assertion, or add a Home-only shim.
Acceptance criteria:
- the authoritative Bun test uses deterministic package content or an immutable upstream revision
- Home keeps the copied test byte-identical to the pinned Bun corpus
- the strict native full bunx file passes with zero failures under both Home and the pinned Bun control
- no bootstrap-only simulation is used for parity credit