Rework windows start and stop methods so that command windows dont appear. Stop with signal since we cannot signint.

toolkit/win_console.py

@@ -0,0 +1,58 @@
+"""Keep child processes from popping console windows on Windows.
+
+The UI worker launches training jobs with pythonw.exe and DETACHED_PROCESS so
+they survive the UI shutting down (see ui/cron/actions/startJob.ts). That
+leaves the job with no console at all, and Windows hands a brand new console
+-- with a visible window -- to any console program launched from a process
+that has none. MSVC during a torch/triton compile, git during a HF download
+and ffmpeg would each flash a window on the user's desktop.
+
+Defaulting those spawns to CREATE_NO_WINDOW suppresses the flash. This is a
+no-op unless we are on Windows *and* have no console, so running run.py from a
+terminal behaves exactly as it did before.
+"""
+
+import subprocess
+import sys
+
+CREATE_NEW_CONSOLE = 0x00000010
+DETACHED_PROCESS = 0x00000008
+CREATE_NO_WINDOW = 0x08000000
+
+# creationflags is the 14th positional parameter of Popen.__init__ after self.
+_CREATIONFLAGS_POSITION = 14
+
+_patched = False
+
+
+def _has_console():
+    import ctypes
+
+    return bool(ctypes.windll.kernel32.GetConsoleWindow())
+
+
+def suppress_child_consoles():
+    """Make CREATE_NO_WINDOW the default for subprocesses, where it matters."""
+    global _patched
+    if _patched or sys.platform != "win32":
+        return
+    try:
+        if _has_console():
+            return
+    except Exception:
+        # Never let a console tweak take down a training run.
+        return
+
+    original_init = subprocess.Popen.__init__
+
+    def patched_init(self, *args, **kwargs):
+        if len(args) >= _CREATIONFLAGS_POSITION:
+            # Passed positionally; leave the caller's choice alone.
+            return original_init(self, *args, **kwargs)
+        flags = kwargs.get("creationflags", 0)
+        if not flags & (CREATE_NEW_CONSOLE | DETACHED_PROCESS | CREATE_NO_WINDOW):
+            kwargs["creationflags"] = flags | CREATE_NO_WINDOW
+        return original_init(self, *args, **kwargs)
+
+    subprocess.Popen.__init__ = patched_init
+    _patched = True