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.

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "pysim-simple-server"
-version = "3.40.3"
+version = "3.40.4"
 description = "HTTP REST server wrapping pysim for the SIMple PWA"
 license = { text = "GPL-2.0-or-later" }
 requires-python = ">=3.9"