Add real-data duration estimates to benchmark and burn pages

- Add BenchmarkEstimated* constants to benchmark_types.go from _v8 logs
  (Standard Perf ~16 min, Standard Power Fit ~43 min, Stability Perf ~92 min)
- Update benchmark profile dropdown to show Perf / Power Fit timing per profile
- Add timing columns to Method Split table (Standard vs Stability per run type)
- Update burn preset labels to show "N min/GPU (sequential) or N min (parallel)"
- Clarify burn "one by one" description with sequential vs parallel scaling

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

audit/internal/platform/benchmark_types.go

@@ -43,6 +43,31 @@ const (
 	NvidiaBenchmarkProfileOvernight = "overnight"
 )
 
+// Estimated wall-clock durations for benchmark runs, derived from real _v8 logs.
+// Rule: when changing profile phase durations in resolveBenchmarkProfile(),
+// re-measure from actual task logs and update the constants here.
+//
+// Sources:
+//   - BenchmarkEstimatedPerfStandardSec:   MLT v8.22 ramp 1-4: 927 s; xFusion v8.22 parallel 8GPU: 1080 s
+//   - BenchmarkEstimatedPerfStabilitySec:  xFusion v8.22 ramp 1-8: 5532 s
+//   - BenchmarkEstimatedPerfOvernightSec:  derived from profile phases (SteadySec=27000)
+//   - BenchmarkEstimatedPowerStandardSec:  MLT v8.22 ramp 1-4: 2663 s; MSI v8.22 ramp 1-8: 2375 s
+//   - BenchmarkEstimatedPowerStabilitySec: xFusion v8.17/v8.22 ramp 1-8: 1977-2002 s
+const (
+	// Performance Benchmark (bee-gpu-burn).
+	// Duration is per full ramp-up run (ramp 1→N) or per single parallel run.
+	// Sequential per-GPU mode scales approximately linearly.
+	BenchmarkEstimatedPerfStandardSec  = 960  // ~16 min; ramp-up 1-4: 927 s, parallel 8GPU: 1080 s
+	BenchmarkEstimatedPerfStabilitySec = 5532 // ~92 min; ramp-up 1-8 measured
+	BenchmarkEstimatedPerfOvernightSec = 8 * 3600
+
+	// Power / Thermal Fit (dcgmi targeted_power binary-search calibration).
+	// Duration is for the full ramp-up run; individual steps vary with convergence speed.
+	BenchmarkEstimatedPowerStandardSec  = 2600 // ~43 min; ramp 1-4: 2663 s, ramp 1-8: 2375 s
+	BenchmarkEstimatedPowerStabilitySec = 2000 // ~33 min; stability profile converges faster (longer steady → faster convergence)
+	BenchmarkEstimatedPowerOvernightSec = 3 * 3600
+)
+
 type NvidiaBenchmarkOptions struct {
 	Profile           string
 	SizeMB            int