feat(tui): GPU Platform Stress Test — live nvtop chart during test

Apply the same pattern as NVIDIA SAT: launch nvtop via tea.ExecProcess
so it occupies the full terminal as a live GPU chart (temp, power, fan,
utilisation lines) while the stress test runs in the background.

- Add screenGPUStressRunning screen + dedicated running/render handlers
- startGPUStressTest: tea.Batch(stress goroutine, tea.ExecProcess(nvtop))
- [o] reopen nvtop at any time; [a] abort (cancels context)
- Graceful degradation: test still runs if nvtop is not on PATH
- gpuStressDoneMsg routes result to screenOutput on completion

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

audit/internal/tui/forms.go

@@ -1,7 +1,6 @@
 package tui
 
 import (
-	"context"
 	"time"
 
 	"bee/audit/internal/platform"
@@ -140,20 +139,7 @@ func (m model) updateConfirm(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 				pollSATProgress("gpu-amd", since),
 			)
 		case actionRunFanStress:
-			m.busyTitle = "GPU Platform Stress Test"
-			m.progressPrefix = "fan-stress"
-			m.progressSince = time.Now()
-			m.progressLines = nil
-			since := m.progressSince
-			opts := hcFanStressOpts(m.hcMode, m.app)
-			return m, tea.Batch(
-				func() tea.Msg {
-					ctx := context.Background()
-					result, err := m.app.RunFanStressTestResult(ctx, opts)
-					return resultMsg{title: result.Title, body: result.Body, err: err, back: screenHealthCheck}
-				},
-				pollSATProgress("fan-stress", since),
-			)
+			return m.startGPUStressTest()
 		}
 	case "ctrl+c":
 		return m, tea.Quit

audit/internal/tui/messages.go

@@ -44,3 +44,9 @@ type nvidiaSATDoneMsg struct {
 	body  string
 	err   error
 }
+
+type gpuStressDoneMsg struct {
+	title string
+	body  string
+	err   error
+}

audit/internal/tui/screen_health_check.go

@@ -3,6 +3,7 @@ package tui
 import (
 	"context"
 	"fmt"
+	"os/exec"
 	"strings"
 
 	tea "github.com/charmbracelet/bubbletea"
@@ -155,6 +156,64 @@ func (m model) hcRunFanStress() (tea.Model, tea.Cmd) {
 	return m, nil
 }
 
+// startGPUStressTest launches the GPU Platform Stress Test and nvtop concurrently.
+// nvtop occupies the full terminal as a live chart; the stress test runs in background.
+func (m model) startGPUStressTest() (tea.Model, tea.Cmd) {
+	opts := hcFanStressOpts(m.hcMode, m.app)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	m.gpuStressCancel = cancel
+	m.gpuStressAborted = false
+	m.screen = screenGPUStressRunning
+	m.nvidiaSATCursor = 0
+
+	stressCmd := func() tea.Msg {
+		result, err := m.app.RunFanStressTestResult(ctx, opts)
+		return gpuStressDoneMsg{title: result.Title, body: result.Body, err: err}
+	}
+
+	nvtopPath, lookErr := exec.LookPath("nvtop")
+	if lookErr != nil {
+		return m, stressCmd
+	}
+
+	return m, tea.Batch(
+		stressCmd,
+		tea.ExecProcess(exec.Command(nvtopPath), func(_ error) tea.Msg {
+			return nvtopClosedMsg{}
+		}),
+	)
+}
+
+// updateGPUStressRunning handles keys on the GPU stress running screen.
+func (m model) updateGPUStressRunning(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
+	switch msg.String() {
+	case "o", "O":
+		nvtopPath, err := exec.LookPath("nvtop")
+		if err != nil {
+			return m, nil
+		}
+		return m, tea.ExecProcess(exec.Command(nvtopPath), func(_ error) tea.Msg {
+			return nvtopClosedMsg{}
+		})
+	case "a", "A":
+		if m.gpuStressCancel != nil {
+			m.gpuStressCancel()
+			m.gpuStressCancel = nil
+		}
+		m.gpuStressAborted = true
+		m.screen = screenHealthCheck
+		m.cursor = 0
+	case "ctrl+c":
+		return m, tea.Quit
+	}
+	return m, nil
+}
+
+func renderGPUStressRunning() string {
+	return "GPU PLATFORM STRESS TEST\n\nTest is running...\n\n[o] Open nvtop  [a] Abort test  [ctrl+c] quit\n"
+}
+
 func (m model) hcRunAll() (tea.Model, tea.Cmd) {
 	for _, sel := range m.hcSel {
 		if sel {

audit/internal/tui/types.go

@@ -27,6 +27,7 @@ const (
 	screenConfirm          screen = "confirm"
 	screenNvidiaSATSetup   screen = "nvidia_sat_setup"
 	screenNvidiaSATRunning screen = "nvidia_sat_running"
+	screenGPUStressRunning screen = "gpu_stress_running"
 )
 
 type actionKind string
@@ -93,6 +94,10 @@ type model struct {
 	nvidiaSATCancel  func()
 	nvidiaSATAborted bool
 
+	// GPU Platform Stress Test running
+	gpuStressCancel  func()
+	gpuStressAborted bool
+
 	// SAT verbose progress (CPU / Memory / Storage / AMD GPU)
 	progressLines  []string
 	progressPrefix string

audit/internal/tui/update.go

@@ -108,6 +108,28 @@ func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		return m.handleNvidiaGPUsMsg(msg)
 	case nvtopClosedMsg:
 		return m, nil
+	case gpuStressDoneMsg:
+		if m.gpuStressAborted {
+			return m, nil
+		}
+		if m.gpuStressCancel != nil {
+			m.gpuStressCancel()
+			m.gpuStressCancel = nil
+		}
+		m.prevScreen = screenHealthCheck
+		m.screen = screenOutput
+		m.title = msg.title
+		if msg.err != nil {
+			body := strings.TrimSpace(msg.body)
+			if body == "" {
+				m.body = fmt.Sprintf("ERROR: %v", msg.err)
+			} else {
+				m.body = fmt.Sprintf("%s\n\nERROR: %v", body, msg.err)
+			}
+		} else {
+			m.body = msg.body
+		}
+		return m, m.refreshSnapshotCmd()
 	case nvidiaSATDoneMsg:
 		if m.nvidiaSATAborted {
 			return m, nil
@@ -152,6 +174,8 @@ func (m model) updateKey(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
 		return m.updateNvidiaSATSetup(msg)
 	case screenNvidiaSATRunning:
 		return m.updateNvidiaSATRunning(msg)
+	case screenGPUStressRunning:
+		return m.updateGPUStressRunning(msg)
 	case screenExportTargets:
 		return m.updateMenu(msg, len(m.targets), m.handleExportTargetsMenu)
 	case screenInterfacePick:

audit/internal/tui/view.go

@@ -78,6 +78,8 @@ func (m model) View() string {
 			body = renderNvidiaSATSetup(m)
 		case screenNvidiaSATRunning:
 			body = renderNvidiaSATRunning()
+		case screenGPUStressRunning:
+			body = renderGPUStressRunning()
 		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: