ap_onboard - portable: put legacy WFX2 modules onto the local wifi

Unzip anywhere (a USB stick is fine), plug in a USB wifi adapter, then from a
command prompt in this folder:

  onboard.cmd --interfaces                       what wifi adapters this PC has
  onboard.cmd --list                             module access points in range
  onboard.cmd --ssid MPUK-DATA --pass "..."      the loop; Ctrl-C to stop

The script drives ONE wifi adapter: --iface "Wi-Fi 2" names it, otherwise it
takes the only one, or the USB / unconnected one. The PC's other adapters,
profiles and routes are never touched. Two things that break it: a VPN client
(it captures 1.2.3.4, which is public address space - disconnect the VPN), and
Windows on another language (netsh output is parsed in English).

It logs to %USERPROFILE%\.ap_onboard.log and remembers finished modules in
%USERPROFILE%\.ap_onboard.json. Bundled Python 3.12 embeddable, unmodified.
