SleeperThread concurrency paths needed stress coverage around wake/stop races.
I added a subprocess stress test that repeatedly interleaves wake_up() and
stop() and verifies the worker exits cleanly.
Signed-off-by: Austin Horstman <khaneliman12@gmail.com>
We needed a regression test for reassignment safety after lifecycle fixes.
I added a subprocess test that reassigns SleeperThread workers and verifies the
process exits normally instead of terminating.
Signed-off-by: Austin Horstman <khaneliman12@gmail.com>
