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>

audit/internal/schema/hardware.go

@@ -20,6 +20,7 @@ type RuntimeHealth struct {
 	ExportDir     string                 `json:"export_dir,omitempty"`
 	DriverReady   bool                   `json:"driver_ready,omitempty"`
 	CUDAReady     bool                   `json:"cuda_ready,omitempty"`
+	NvidiaGSPMode string                 `json:"nvidia_gsp_mode,omitempty"` // "gsp-on", "gsp-off", "gsp-stuck"
 	NetworkStatus string                 `json:"network_status,omitempty"`
 	Issues        []RuntimeIssue         `json:"issues,omitempty"`
 	Tools         []RuntimeToolStatus    `json:"tools,omitempty"`