refactor(webui): redesign Burn tab and fix gpu-burn memory defaults

- Burn tab: replace 6 flat cards with 3 grouped cards (GPU Stress,
  Compute Stress, Platform Thermal Cycling) + global Burn Profile
- Run All button at top enqueues all enabled tests across all cards
- GPU Stress: tool checkboxes enabled/disabled via new /api/gpu/tools
  endpoint based on driver status (/dev/nvidia0, /dev/kfd)
- Compute Stress: checkboxes for cpu/memory-stress/stressapptest
- Platform Thermal Cycling: component checkboxes (cpu/nvidia/amd)
  with platform_components param wired through to PlatformStressOptions
- bee-gpu-burn: default size-mb changed from 64 to 0 (auto); script
  now queries nvidia-smi memory.total per GPU and uses 95% of it
- platform_stress: removed hardcoded --size-mb 64; respects Components
  field to selectively run CPU and/or GPU load goroutines

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

audit/internal/webui/tasks.go

@@ -106,9 +106,10 @@ type taskParams struct {
 	GPUIndices        []int  `json:"gpu_indices,omitempty"`
 	ExcludeGPUIndices []int  `json:"exclude_gpu_indices,omitempty"`
 	Loader            string `json:"loader,omitempty"`
-	BurnProfile       string `json:"burn_profile,omitempty"`
-	DisplayName       string `json:"display_name,omitempty"`
-	Device            string `json:"device,omitempty"` // for install
+	BurnProfile        string   `json:"burn_profile,omitempty"`
+	DisplayName        string   `json:"display_name,omitempty"`
+	Device             string   `json:"device,omitempty"` // for install
+	PlatformComponents []string `json:"platform_components,omitempty"`
 }
 
 type persistedTask struct {
@@ -550,6 +551,7 @@ func (q *taskQueue) runTask(t *Task, j *jobState, ctx context.Context) {
 			break
 		}
 		opts := resolvePlatformStressPreset(t.params.BurnProfile)
+		opts.Components = t.params.PlatformComponents
 		archive, err = a.RunPlatformStress(ctx, "", opts, j.append)
 	case "audit":
 		if a == nil {