Windows: stop.bat doesn't stop Python nodes ("Skipping PID ... not a concore process") #652

On Windows, stop.bat leaves Python nodes running. The concorekill.bat that concore.py writes only kills a registered PID if its command line contains "concore":

... CommandLine" 2>nul | findstr /i "concore" >nul

but a node's command line is just "...\python.exe" "controller.py", so every PID is skipped:

Skipping PID 38880 - not a concore process or not running
Skipping PID 19912 - not a concore process or not running

Steps (Windows 11, dev @ 8f3e444; run.bat needs #639 to start the nodes at all):

1. python mkconcore.py demo/sample.graphml demo out windows, then cd out, build.bat, maxtime.bat 100000, run.bat
2. While the nodes are running (PIDs are in CZ\concorekill_pids.txt / PZ\concorekill_pids.txt), run stop.bat
3. Both PIDs are skipped and the python processes keep running.

The Windows test for the kill script passes because it starts its process as python -c "..." concore_node, which puts "concore" on the command line; CI doesn't run it (ubuntu only).

I have a small fix with tests and will open a PR against dev.