Introduce scale_timeout(mode) to centralize test timeout scaling logic based on build mode, the function will return a callable that will handle the timeout by mode.
This ensures consistent timeout behavior across test helpers and eliminates ad-hoc per-test scaling adjustments.
Centralizing the logic improves maintainability and makes timeout behavior easier to reason about.
This becomes increasingly important as we run tests on heterogeneous hardware configurations.
Different build modes (especially debug) can significantly affect execution time, and having a single scaling mechanism helps keep test stability predictable across environments.
No functional change beyond unifying existing timeout scaling behavior.
