feat: task queue, UI overhaul, burn tests, install-to-RAM

- Task queue: all SAT/audit jobs enqueue and run one-at-a-time;
  tasks persist past page navigation; new Tasks page with cancel/priority/log stream
- UI: consolidate nav (Validate, Burn, Tasks, Tools); Audit becomes modal;
  Dashboard hardware summary badges + split metrics charts (load/temp/power);
  Tools page consolidates network, services, install, support bundle
- AMD GPU: acceptance test and stress burn cards; GPU presence API greys
  out irrelevant SAT cards automatically
- Burn tests: Memory Stress (stress-ng --vm), SAT Stress (stressapptest)
- Install to RAM: copies squashfs to /dev/shm, re-associates loop devices
  via LOOP_CHANGE_FD ioctl so live media can be ejected
- Charts: relative time axis (0 = now, negative left)
- memtester: LimitMEMLOCK=infinity in bee-web.service; empty output → UNSUPPORTED
- SAT overlay applied dynamically on every /audit.json serve
- MIME panic guard for LiveCD ramdisk I/O errors
- ISO: add memtest86+, stressapptest packages; memtest86+ GRUB entry;
  disable screensaver/DPMS in bee-openbox-session
- Unknown SAT status severity = 1 (does not override OK)

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

audit/internal/platform/live_metrics.go

@@ -32,9 +32,12 @@ type TempReading struct {
 func SampleLiveMetrics() LiveMetricSample {
 	s := LiveMetricSample{Timestamp: time.Now().UTC()}
 
-	// GPU metrics — skipped silently if nvidia-smi unavailable
-	gpus, _ := SampleGPUMetrics(nil)
-	s.GPUs = gpus
+	// GPU metrics — try NVIDIA first, fall back to AMD
+	if gpus, err := SampleGPUMetrics(nil); err == nil && len(gpus) > 0 {
+		s.GPUs = gpus
+	} else if amdGPUs, err := sampleAMDGPUMetrics(); err == nil && len(amdGPUs) > 0 {
+		s.GPUs = amdGPUs
+	}
 
 	// Fan speeds — skipped silently if ipmitool unavailable
 	fans, _ := sampleFanSpeeds()