Handle NVIDIA GSP firmware init hang with timeout fallback

- bee-nvidia-load: run insmod in background, poll /proc/devices for
  nvidiactl; if GSP init doesn't complete in 90s, kill insmod and retry
  with NVreg_EnableGpuFirmware=0. Handles EBUSY case with clear error.
- Write /run/bee-nvidia-mode (gsp-on/gsp-off/gsp-stuck) for audit layer
- Show GSP mode badge in sidebar: yellow for gsp-off, red for gsp-stuck
- Report NvidiaGSPMode in RuntimeHealth with issue entries
- Simplify GRUB menu: default (KMS+GSP), advanced submenu (GSP=off,
  nomodeset, fail-safe), remove load-to-RAM entry
- Add pcmanfm, ristretto, mupdf, mousepad to desktop packages

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

iso/builder/config/package-lists/bee.list.chroot

@@ -65,6 +65,10 @@ python3-pil
 xorg
 xterm
 chromium
+mousepad
+pcmanfm
+ristretto
+mupdf
 xserver-xorg-video-fbdev
 xserver-xorg-video-vesa
 lightdm