feat: bc-250 support

[disconn3ct]

This is a roll-up of everything I needed to get it working on a BC-250. It still requires manually setting encoder=software in ~/.config/sunshine/sunshine.conf (BC-250 has no video encoding)

• Adds trixie-backports if ENABLE_SID=false
  • Backports provides Mesa 26.1.2
• Add radeontop, nvtop tools
• Explicitly select Sid or Trixie-Backports when installing Mesa
• Adds FORCE_X11_DUMMY_CONFIG=AMD to use the AMD configuration from [Bug]: Missing DRI3 Support #168
• Fixes [Bug]: crash loop in sunshine due to system tray icon #233 (disable the tray icon)

Zero AI, all human.

[disconn3ct]

As a note to anyone trying this, setting FORCE_X11_DUMMY_CONFIG=AMD will activate the DisplayPort output.

[Josh5]

Thanks for the contribution! I've taken the Sunshine system-tray fix separately, as it directly addresses the reported issue.

I'm going to leave the remaining BC-250 changes out of the current release. In particular, repurposing the documented boolean FORCE_X11_DUMMY_CONFIG variable with an AMD value would need a broader refactor and documentation update, and enabling Trixie backports in the main image would introduce a wider package surface that I cannot reasonably validate for all supported hardware.

The upcoming v2 release, expected in the coming weeks, is rebased on Fedora 44 and is intended to support your hardware without these changes.

Thanks again for the PR, and happy gaming on your AMD BC-250!