Derive Darwin subprocess test budgets from the bounded ownership compiler budget while preserving short command deadlines. Always join the retained command scope after test failures.
Refs #5094.
Prepare native process ownership outside short command deadlines. Reuse the shared cleanup adapter and resource scope for direct/nested preparation failures and command cleanup.
Fixes#5094.
Use shared owned command supervision for all evaluation helpers, join streamed output, and retain/retry incomplete cleanup before deleting run files.
Fixes#5094.