start/sniff-start: refuse to run in Windows-hosted shells

A Windows user could run the bash launchers from WSL or Git Bash / MSYS2 /
MinGW / Cygwin, where the Linux USB assumptions do not hold: WSL cannot reach
the Windows SIMtrace2 device, and those shells have no Linux /sys + /dev/bus/usb
view for the udev pre-flight.  Both launchers now detect a Windows host up
front (WSL via /proc/version, the rest via uname -s) and exit 2 with a pointer
at the matching .bat launcher, which drives the Windows Python/PyUSB stack.
The message goes to stderr; a deliberate WSL/Cygwin flow can still run the
Python module directly (noted in the source comment).

Tests: tests/test_launchers.py runs each script with a fake mingw uname and
asserts exit 2 plus the start.bat/sniff-start.bat pointer, pins the WSL
detection, and checks bash -n syntax (skipped when bash is absent).

Bumps 2.7.14 (version.py, pyproject, PWA_VERSION), SW cache v96, the README
download examples and the release-notes preamble.  561 Python + 80 Node tests.

frontend/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'simtrace-analyser-v95';
+const CACHE = 'simtrace-analyser-v96';
 
 const PRECACHE = [
     'index.html',