feat(Hardware Support): Add AYANEO NEXT 2 device and capability map

[EightQuarterBit]

This PR implements support for the AYANEO NEXT 2, according to the issue opened here. After looking through the repo it seemed simple enough to implement myself, though I did hand off the legwork of writing the YAML files to Claude Sonnet 5, as well as having it verify I wasn't missing a file that needed to be modified.

The exact prompt I gave to Claude was:

If I wanted to add support for my AYANEO NEXT 2 according to this issue: #654 what modifications would I need to perform to the files in the repo?

That spat out the device and capability map, mostly cribbed from existing Ayaneo config. I went back and forth with Claude to see if there were better options than an Xbox Elite controller for this device, and to check up on LC/RC button functions, but in the end the only change I made to the generated config was renaming the "Ayaneo Button" from "Logo". I named it "Logo" in the issue, but it's labeled "Ayaneo Button" in existing capability maps, so that seemed like the better convention.

Tested on Bazzite Deck 44 by installing to /etc/inputplumber/devices.d/ and /etc/inputplumber/capability_maps.d/. After restarting InputPlumber, the built-in controller appeared as an Xbox Elite controller as expected. Back buttons were visible and successfully mapped/tested in Steam. The "Ayaneo Button" also correctly summons Quick Access. "T" button is mapped to QuickAccess2, which seems to take a screenshot in-game at the moment.

A second, "ghost" Xbox Elite 2 controller also appeared on the system, though I've read reports of other users encountering the same behavior, so I'm assuming that's not a misconfiguration with these files. Claude seems to think it's InputPlumber generating a child Xbox Elite controller from my remapped physical controller. Surfacing it just in case that's not expected.

The "=" button was left emitting its default key combo since there didn't seem to be a better unopinionated option.

The LC and RC buttons, of course, weren't visible in Steam for mapping, since they aren't present on an Xbox Elite controller.

I haven't yet found a completely satisfactory way to test the gyro/accelerometer orientation, since that's not implemented on the Xbox Elite controller. There's no kernel-level mount matrix for this under /sys/bus/iio/devices/iio:device0/in_mount_matrix, but watching the raw accelerometer output with watch -n 0.2 'for f in /sys/bus/iio/devices/iio:device0/in_accel_x_raw; do echo "$f: $(cat $f)"; done' (repeat for Y and Z) it seemed to generate sensible values.

Likewise I could not test setting the controller LED rings via InputPlumber in any way I or Claude could determine.

Happy to test further on either of those features if a more thorough test regimen can be recommended.