Wires `xbox_windows` into the per-pad router so an Xbox-family pad can be built as a real
HID device instead of the XUSB companion, and adds the knob that selects between them.
Opt-in rather than the new default, deliberately. XUSB is what classic-XInput games read
today; the HID pad buys the Steam / WGI / GameInput / DirectInput visibility XUSB can
never have, but whether Windows promotes it into an Xbox-profile device that XInput and
WGI Gamepad accept is still the open question. Flipping the default before that is
settled would trade a known-working path for an unproven one. The two backends are
mutually exclusive per pad by construction — one match arm or the other — because
presenting both hands a game two controllers for one pair of hands.
Verified on .173: cargo check -p punktfunk-host exit 0, clippy -D warnings clean,
`cargo test -p punktfunk-host gamepad` 8/8 green, fmt clean.
enricobuehler
4e04c2bbf8