Adds scenario 11, which races a real hardlink_clone_into against a real,
concurrent publish-snapshot.sh republish of the exact snapshot being
cloned, and asserts the publisher's own log reports entering its
reader-drain wait. Deleting reader_lock_acquire left every suite green
at the identical 129 assertions (issue #10): the marker it writes is
what the publisher's wait_for_readers checks, and with it gone the
publisher sees zero readers on its first check and proceeds straight to
reclaiming the rotated generation, silently.
Kept as its own scenario rather than folded into 8a: 8a already pins
exactly one property (the identity check) for exactly one mutant, and
the suite's one-scenario-one-mutant diagonal across 8a to 8d and 10 is
deliberate.
claude
0c12af4e43
