Function is_process_alive 

pub fn is_process_alive(pid: u32) -> bool

#576 already fixed this exact hardcoded-true anti-pattern for daemon::is_daemon_running by delegating to ipc::process::is_alive (which has a real Windows OpenProcess check); this duplicate copy was missed, so on non-unix targets cleanup_stale could never flip a dead MCP session’s entry to Finished, leaving registry.json accumulating stale Active entries forever — the root cause of the “N active agents” dashboard bug on Windows.