refactor: harden diagnostics and consolidate runtime code

audit/internal/platform/live_metrics.go

@@ -293,6 +293,10 @@ func sampleLiveTempsViaIPMI() []TempReading {
 }
 
 func firstTempInputValue(feature map[string]any) (float64, bool) {
+	return firstSensorInputValue(feature, "temp")
+}
+
+func firstSensorInputValue(feature map[string]any, kind string) (float64, bool) {
 	keys := make([]string, 0, len(feature))
 	for key := range feature {
 		keys = append(keys, key)
@@ -300,7 +304,7 @@ func firstTempInputValue(feature map[string]any) (float64, bool) {
 	sort.Strings(keys)
 	for _, key := range keys {
 		lower := strings.ToLower(key)
-		if !strings.Contains(lower, "temp") || !strings.HasSuffix(lower, "_input") {
+		if !strings.Contains(lower, kind) || !strings.HasSuffix(lower, "_input") {
 			continue
 		}
 		switch value := feature[key].(type) {