Add real-data duration estimates to validate tab profiles

- Add SATEstimated* constants to sat.go derived from _v8 production logs,
  with a rule to recalculate them whenever the script changes
- Extend validateInventory with NvidiaGPUCount to make estimates GPU-aware
- Update all validate card duration strings: CPU, memory, storage, NVIDIA GPU,
  targeted stress/power, pulse test, NCCL, nvbandwidth
- Fix nvbandwidth description ("intended to stay short" → actual ~45 min)
- Top-level profile labels show computed total including GPU count

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

audit/internal/webui/server_test.go

@@ -754,9 +754,9 @@ func TestValidatePageRendersNvidiaFabricCardsInValidateMode(t *testing.T) {
 	body := rec.Body.String()
 	for _, needle := range []string{
 		`NVIDIA Interconnect (NCCL)`,
-		`Runs in Validate and Stress.`,
+		`Validate and Stress:`,
 		`NVIDIA Bandwidth (NVBandwidth)`,
-		`Intended to stay short enough for Validate.`,
+		`nvbandwidth runs all built-in tests without a time limit`,
 	} {
 		if !strings.Contains(body, needle) {
 			t.Fatalf("validate page missing %q: %s", needle, body)