Replace native GFN (impossible on this GPU) with browser GFN + Moonlight

The native GeForce NOW client hard-requires Vulkan video-decode
extensions (error 0xC0F11312) and the BC-250 has no video decode
hardware — unfixable at driver level. Replaced with:
- Chromium + a GeForce NOW web-app shortcut (works on Linux Chromium
  without UA tricks nowadays; CPU-decoded 1080p)
- Moonlight client for streaming from a home Sunshine host (planned:
  VM with RTX 3050 passthrough on the R730)
Drops bc250-gfn-install service/script.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

files/console/usr/share/applications/geforce-now-web.desktop

@@ -0,0 +1,9 @@
+[Desktop Entry]
+Type=Application
+Name=GeForce NOW
+Comment=NVIDIA cloud gaming in the browser (the native app requires hardware video decode this GPU does not have)
+Exec=flatpak run org.chromium.Chromium --app=https://play.geforcenow.com/
+Icon=input-gaming
+Terminal=false
+Categories=Game;
+StartupNotify=true