Translate report to English; add power anomaly detector

All report strings are now English only.

Add detectPowerAnomaly: scans steady-state metric rows per GPU with a
5-sample rolling baseline; flags a sudden drop ≥30% while GPU usage >50%
as [HARD STOP] — indicates bad cable contact or VRM fault.

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

audit/internal/platform/benchmark.go

@@ -508,6 +508,10 @@ func (s *System) RunNvidiaBenchmark(ctx context.Context, baseDir string, opts Nv
 
 			gpuResult.Scores = scoreBenchmarkGPUResult(gpuResult)
 			gpuResult.DegradationReasons = detectBenchmarkDegradationReasons(gpuResult, result.Normalization.Status)
+			if anomaly := detectPowerAnomaly(metricRows, idx); anomaly != "" {
+				gpuResult.Notes = append(gpuResult.Notes,
+					fmt.Sprintf("[HARD STOP] GPU %d: %s", idx, anomaly))
+			}
 			if planErr != nil {
 				gpuResult.Status = classifySATErrorStatus(phaseLogs["mixed"], planErr)
 			} else if len(gpuResult.PrecisionFailures) > 0 {
@@ -1480,6 +1484,53 @@ func serverQualityScore(score BenchmarkScorecard) float64 {
 	return clampScore(q * 100)
 }
 
+// detectPowerAnomaly scans per-GPU steady-state metric rows for a sudden
+// power drop — a symptom of bad cable contact, VRM fault, or thermal event
+// on the power delivery path. Returns a non-empty string if an anomaly is found.
+//
+// Algorithm: uses a 5-sample rolling baseline; flags any sample that falls
+// more than 30% below the baseline while the GPU was otherwise loaded
+// (usage > 50%). A sustained throttle (power cap) is not flagged here —
+// that is already captured by PowerCapThrottlePct.
+func detectPowerAnomaly(rows []GPUMetricRow, gpuIndex int) string {
+	const windowSize = 5
+	const dropThresholdPct = 30.0
+	const minUsagePct = 50.0
+
+	// Filter rows for this GPU during steady state only.
+	var steady []GPUMetricRow
+	for _, r := range rows {
+		if r.GPUIndex == gpuIndex && r.Stage != "" && strings.Contains(r.Stage, "steady") {
+			steady = append(steady, r)
+		}
+	}
+	if len(steady) < windowSize+2 {
+		return ""
+	}
+
+	// Compute initial baseline from the first window.
+	var baseSum float64
+	for i := 0; i < windowSize; i++ {
+		baseSum += steady[i].PowerW
+	}
+
+	for i := windowSize; i < len(steady); i++ {
+		baseline := baseSum / float64(windowSize)
+		sample := steady[i]
+		if baseline > 0 && sample.UsagePct >= minUsagePct {
+			dropPct := (baseline - sample.PowerW) / baseline * 100
+			if dropPct >= dropThresholdPct {
+				return fmt.Sprintf("sudden power drop detected at t=%.0fs: %.0f W → %.0f W (%.0f%% below rolling baseline) — possible bad cable contact or VRM fault",
+					sample.ElapsedSec, baseline, sample.PowerW, dropPct)
+			}
+		}
+		// Slide the window baseline.
+		baseSum -= steady[i-windowSize].PowerW
+		baseSum += sample.PowerW
+	}
+	return ""
+}
+
 func detectBenchmarkDegradationReasons(gpu BenchmarkGPUResult, normalizationStatus string) []string {
 	var reasons []string
 	runtimeUS := math.Max(1, gpu.Steady.DurationSec*1e6)