start/setup/update.sh: refuse to run on a Windows-hosted shell

A Windows user running the bash helper scripts (WSL, or Git Bash /
MSYS2 / MinGW / Cygwin) used to fail deep in the venv/PC-SC logic - under
WSL the Linux guest cannot reach the Windows PC/SC readers, and a
mingw/msys shell has the wrong (bin/) venv layout.  Each helper now
detects Windows (WSL via /proc/version, mingw/msys/cygwin via uname -s)
up front and exits 2 with a pointer at the matching .bat script.  Users
who deliberately want the WSL/Cygwin flow can run the underlying commands
directly, without the helpers.

Bumps VERSION to 3.40.4 and the SW cache to simple-v490.

tests/test_setup_scripts.py

@@ -39,6 +39,11 @@ class SetupShTests(unittest.TestCase):
                              capture_output=True, text=True)
         self.assertEqual(res.returncode, 0, res.stderr)
 
+    def test_windows_guard_points_to_setup_bat(self):
+        self.assertIn('microsoft /proc/version', self.src)
+        self.assertIn('MINGW|MSYS|CYGWIN', self.src)
+        self.assertIn('Use setup.bat from a Windows command prompt', self.src)
+
 
 class SetupBatTests(unittest.TestCase):
     def setUp(self):