feat(dcgm): add NVIDIA DCGM diagnostics, fix KVM console

- Add 9002-nvidia-dcgm.hook.chroot: installs datacenter-gpu-manager
  from NVIDIA apt repo during live-build
- Enable nvidia-dcgm.service in chroot setup hook
- Replace bee-gpu-stress with dcgmi diag (levels 1-4) in NVIDIA SAT
- TUI: replace GPU checkbox + duration UI with DCGM level selection
- Remove console=tty2 from boot params: KVM/VGA now shows tty1
  where bee-tui runs, fixing unresponsive console

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

audit/internal/tui/messages.go

@@ -32,11 +32,6 @@ type snapshotMsg struct {
 	panel  app.HardwarePanelData
 }
 
-type nvidiaGPUsMsg struct {
-	gpus []platform.NvidiaGPU
-	err  error
-}
-
 type nvtopClosedMsg struct{}
 
 type nvidiaSATDoneMsg struct {