concore stop reports success on Windows even when taskkill fails

[avinxshKD]

In concore_cli/commands/stop.py, the Windows kill path uses check=False and never looks at the return code:

subprocess.run(['taskkill', '/F', '/PID', str(pid)], 
             capture_output=True, 
             check=False)                    # never raises
console.print(f"  ✓ Stopped {name}")         # always prints success
killed_count += 1                            # always counts as killed

On POSIX, a failed terminate() raises TimeoutExpired which gets caught and escalated to kill(). There's actual feedback.

On Windows, if taskkill fails (Access Denied, PID not found, protected process), execution falls through silently and the user sees "Successfully stopped all N process(es)" when nothing was actually stopped.

The fix is straightforward: check result.returncode != 0 and raise or log accordingly, thx

[avinxshKD]

pls review when u get chance @pradeeban