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.

update.sh

@@ -2,6 +2,19 @@
 # Update this packaged SIMple install in place (see tools/update.py --help).
 # The .venv is reused - pysim and its prerequisites are not re-installed.
 set -e
+
+# Windows guard: update.sh is the native Linux/macOS helper.  Under WSL the
+# Linux guest cannot reach the Windows PC/SC readers, and a Git Bash / MSYS2 /
+# MinGW / Cygwin shell has the wrong (bin/) venv layout - use update.bat.  A
+# deliberate WSL/Cygwin flow can run tools/update.py without this script.
+if grep -qi microsoft /proc/version 2>/dev/null || \
+   uname -s 2>/dev/null | grep -qiE 'MINGW|MSYS|CYGWIN'; then
+    echo "Error: update.sh is the Linux/macOS helper and cannot run on Windows"
+    echo "(WSL / MSYS2 / MinGW / Cygwin detected)."
+    echo "Use update.bat from a Windows command prompt (cmd.exe / PowerShell) instead."
+    exit 2
+fi
+
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
 if [ -x "$SCRIPT_DIR/.venv/bin/python" ]; then
     PY="$SCRIPT_DIR/.venv/bin/python"