feat(tui): live GPU chart during stress test, full VRAM allocation

- GPU Platform Stress Test now shows a live in-TUI chart instead of nvtop.
  nvidia-smi is polled every second; up to 60 data points per GPU kept.
  All three metrics (Usage %, Temp °C, Power W) drawn on a single plot,
  each normalised to its own range and rendered in a different colour.
- Memory allocation changed from MemoryMB/16 to MemoryMB-512 (full VRAM
  minus 512 MB driver overhead) so bee-gpu-stress actually stresses memory.

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

audit/internal/tui/view.go

@@ -79,7 +79,7 @@ func (m model) View() string {
 		case screenNvidiaSATRunning:
 			body = renderNvidiaSATRunning()
 		case screenGPUStressRunning:
-			body = renderGPUStressRunning()
+			body = renderGPUStressRunning(m)
 		case screenOutput:
 			body = fmt.Sprintf("%s\n\n%s\n\n[enter/esc] back  [ctrl+c] quit\n", m.title, strings.TrimSpace(m.body))
 		default: