FEATURE-ci-darwin-header-deadline: Control unmodified native package prefix

Use the exact c0 checkout/archive and original selected_archive/package_lane helpers for one root-context shared TLS-off control through native_http1_e2e and external_http1_e2e. Stop only after original suite/required-case/status receipts validate, preserving original failures and excluding remaining matrix work. Remove the trace overlay and native exec wrapper from this control. Collect at most one bounded native sample for the exact stalled target through the original non-reaping command-tree hook; retain ownership and stdout capture. Real helper/compiled-receipt and owned-process tests verify partial-stop timing, failure propagation, no recursive sampling and PID reservation when the child exits during collection. Syntax/identity checks pass; native control and collector evidence remain pending.

Author: etr