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.

.github/release-notes.md

@@ -13,6 +13,10 @@ The source archive is the same tree a clone would have: unzip it and run
 `./start.sh` (Linux/macOS) or `start.bat` (Windows).  Direct SIMtrace2 capture
 on Linux additionally needs the attached `70-simtrace2-pysniff.rules` udev rule.
 
+The `.sh` launchers are for Linux/macOS only: on Windows use `start.bat` /
+`sniff-start.bat` from `cmd.exe` or PowerShell (WSL, Git Bash, MSYS2, MinGW and
+Cygwin are refused).
+
 **Runtime zip (no installer)** — `simtrace-analyser-*.zip`
 is the runtime tree only (packages, PWA, launchers, docs — no tests, no git):
 extract it anywhere and run `start.bat` (Windows) or `./start.sh`