webui: add "6. Scenario" page — run scriptable test scenarios from removable media through the normal task queue

Exposes the scenario engine (platform.System.RunScenario, added earlier)
in the web UI instead of only the `bee run` CLI: a new nav item lists every
scenarios/*.json found on mounted removable media (GET /api/scenario/list)
and runs one with a click (POST /api/scenario/run), enqueued as a normal
Task with target "scenario" — progress/logs live in Tasks like any other
SAT pack, no separate live-output UI needed.

- app.go: satRunner gains RunScenario, exportManager gains
  ListScenarioFilesOnRemovableMedia/ReadScenarioFromRemovableMedia — both
  already implemented on platform.System, just newly exposed through App.
- webui/tasks.go: taskParams.ScenarioName; runTask's "scenario" case reads
  the file from removable media, parses it, and runs it.
- webui/page_scenario.go: the page itself.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

audit/internal/app/app.go

@@ -73,6 +73,8 @@ type serviceManager interface {
 type exportManager interface {
 	ListRemovableTargets() ([]platform.RemovableTarget, error)
 	ExportFileToTarget(src string, target platform.RemovableTarget) (string, error)
+	ListScenarioFilesOnRemovableMedia() ([]platform.ScenarioFileOnRemovableMedia, error)
+	ReadScenarioFromRemovableMedia(name string) ([]byte, error)
 }
 
 type toolManager interface {
@@ -154,6 +156,7 @@ type satRunner interface {
 	RunFanStressTest(ctx context.Context, baseDir string, opts platform.FanStressOptions) (string, error)
 	RunPlatformStress(ctx context.Context, baseDir string, opts platform.PlatformStressOptions, logFunc func(string)) (string, error)
 	RunNCCLTests(ctx context.Context, baseDir string, gpuIndices []int, logFunc func(string)) (string, error)
+	RunScenario(ctx context.Context, baseDir string, spec platform.ScenarioSpec, logFunc func(string)) (string, error)
 }
 
 type runtimeChecker interface {

audit/internal/app/app_install.go

@@ -14,6 +14,20 @@ func (a *App) ListRemovableTargets() ([]platform.RemovableTarget, error) {
 	return a.exports.ListRemovableTargets()
 }
 
+// ListScenarioFilesOnRemovableMedia lists scenarios/*.json found on any
+// mounted removable target (e.g. the blackbox USB stick) — see
+// platform.System.ListScenarioFilesOnRemovableMedia.
+func (a *App) ListScenarioFilesOnRemovableMedia() ([]platform.ScenarioFileOnRemovableMedia, error) {
+	return a.exports.ListScenarioFilesOnRemovableMedia()
+}
+
+// ReadScenarioFromRemovableMedia reads scenarios/<name>.json from whichever
+// mounted removable target has it — see
+// platform.System.ReadScenarioFromRemovableMedia.
+func (a *App) ReadScenarioFromRemovableMedia(name string) ([]byte, error) {
+	return a.exports.ReadScenarioFromRemovableMedia(name)
+}
+
 func (a *App) ExportLatestAudit(target platform.RemovableTarget) (string, error) {
 	if _, err := os.Stat(DefaultAuditJSONPath); err != nil {
 		return "", err

audit/internal/app/app_packs.go

@@ -17,6 +17,17 @@ func (a *App) RunNvidiaAcceptancePack(baseDir string, logFunc func(string)) (str
 	return a.sat.RunNvidiaAcceptancePack(baseDir, logFunc)
 }
 
+// RunScenario runs a user-authored ScenarioSpec (see
+// platform.ParseScenarioJSON) — the webui Scenario page and `bee run` CLI
+// command both go through this so a scenario run gets the same SAT base
+// directory default as every other pack.
+func (a *App) RunScenario(ctx context.Context, baseDir string, spec platform.ScenarioSpec, logFunc func(string)) (string, error) {
+	if strings.TrimSpace(baseDir) == "" {
+		baseDir = DefaultSATBaseDir
+	}
+	return a.sat.RunScenario(ctx, baseDir, spec, logFunc)
+}
+
 func (a *App) RunNvidiaAcceptancePackResult(baseDir string) (ActionResult, error) {
 	path, err := a.RunNvidiaAcceptancePack(baseDir, nil)
 	body := "Archive written."

audit/internal/app/app_test.go

@@ -91,6 +91,14 @@ func (f fakeExports) ExportFileToTarget(src string, target platform.RemovableTar
 	return "", nil
 }
 
+func (f fakeExports) ListScenarioFilesOnRemovableMedia() ([]platform.ScenarioFileOnRemovableMedia, error) {
+	return nil, nil
+}
+
+func (f fakeExports) ReadScenarioFromRemovableMedia(name string) ([]byte, error) {
+	return nil, nil
+}
+
 type fakeRuntime struct {
 	collectFn func(string) (schema.RuntimeHealth, error)
 	dumpFn    func(string) error
@@ -332,6 +340,10 @@ func (f fakeSAT) RunNCCLTests(_ context.Context, baseDir string, gpuIndices []in
 	return "", nil
 }
 
+func (f fakeSAT) RunScenario(_ context.Context, baseDir string, _ platform.ScenarioSpec, _ func(string)) (string, error) {
+	return "", nil
+}
+
 func TestRunNCCLTestsPassesSelectedGPUs(t *testing.T) {
 	t.Parallel()