Handle multiprocessing start methods besides fork

Since Python 3.14 'forkserver' is now the default multiprocessing start
method instead of 'fork', and with this spawn method we need to pass the
`multiprocessing.Event` that we're sharing between the pytest process
and the monitoring process along explicitly, rather than counting on
a `fork()` to share the same object between the two processes.

Author: godlygeek

src/pytest_pystack/_monitor_process.py

@@ -20,6 +20,7 @@ def start(config):
             config,
             os.getpid(),
             _queue,
+            debug_detected,
         ),
         name="pystack_monitor",
     )
@@ -35,7 +36,7 @@ def stop():
             _process.kill()
 
 
-def _run_monitor(config: PystackConfig, pid, queue):
+def _run_monitor(config: PystackConfig, pid, queue, debug_detected):
     pystack_cmd = [
         config.pystack_path,
         "remote",