[r3dbars]

Summary

Fixes #2256.

• Require the existing native-account isolation policy before a launch benchmark stages or launches anything. Recheck the account and running Transcripted processes before every sample; never quit the owner's app.
• Preflight the verification speed lane before building. Isolation/owner-running blocks are exit 3 / SKIP, while broken preflights remain failures.
• Preserve the complete-sample requirement and 400 ms p95 budget; no bypass flags or baseline increases.
• Add nine inert script-level regressions to the required Linux suite and mapped checks. Correct the verification guide's claim that a throwaway HOME isolates macOS preferences.

Independent review and proof

The complete patch was independently approved at c60122434c7b7250dc0ce10720175e14923dab69 against the frozen integration candidate. This main-based commit 9ea264468e3a1d373b9035042c4d883e8089ed56 has the identical stable patch-id 6e870a54676ddae6bd803257b94f14a62891faf9; no unrelated integration changes are included here.

• Original script reproduction: six safety tests fail; two allowed-path tests pass. All native tools and process signals replaced in an owned scratch copy; no real app launch.
• Fixed script behavior: 9/9 regressions pass, independently rerun.
• Existing native isolation policy: 6/6 pass, independently rerun.
• Shell syntax, diff-check and targeted static guards pass.

Full combined regression and exact-head CI are pending; keeping this draft until those gates complete. Real native launch/UI/import/hardware performance is unverified on the owner's account. A safe SKIP or fake 40 ms fixture is not actual app-latency proof. No running app, saved data, permissions or credentials were changed.

[r3dbars]

Final review: the complete repair diff was independently approved, its original defect reproduced, and its regression tests passed. Exact repair-head CI is green. Combined candidate 75488fb passed mapped checks, fresh full deterministic QA/build and safe synthetic paste verification; see #2255 for evidence and the explicit native, thin-packaging and release limitations. Ready for the owner-authorized ancestry-preserving integration; no release or live hardware clearance is implied.