What: the Windows pid_is_alive opens the process with SYNCHRONIZE and returns WaitForSingleObject(h, 0) == WAIT_TIMEOUT; access denied still reads alive via liveness_from_open_error.
Why: GetExitCodeProcess == STILL_ACTIVE (259) is also what a process that exited with code 259 reports while any handle keeps its object, and its creation time still matches the v2 marker, so Busy had no age bound. Python's _early_recovery already uses the wait probe.
Red: Windows-only; marker_tests::pid_is_alive_false_for_an_exited_process_whose_exit_code_is_259 (cfg(windows)) needs a native runner.
Green: cargo check --tests --target x86_64-pc-windows-msvc clean on the real marker.rs (std-only harness); Linux marker tests 49 passed.
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