Keep one behavioural test per probe site: a sibling-namespace session
turn lease is not stolen (hermes_state lease/lock gate), and a
foreign-namespace flock holder record is not broken while same-ns and
unstamped dead records still are (hermes_state_common). The local
namespace is pinned via _LOCAL_PID_NS so both run on every host rather
than only on Linux. The matrix/parse/helper tests re-asserted the same
rule through private seams.
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