Fix normalizer sidecar log and coverage test (#4)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/Recordingtest.Normalizer/Rules.cs

@@ -163,6 +163,66 @@ public static class Rules
         return false;
     }
 
+    /// <summary>
+    /// Allowlist of field names whose values are known to be volatile boolean/scalar
+    /// settings (per docs/sut-catalog/json-configs.json). The values are replaced with
+    /// a deterministic placeholder so golden-file comparisons stay stable while still
+    /// preserving the field's presence and key order.
+    /// </summary>
+    public static readonly HashSet<string> VolatileSettingFieldNames = new(StringComparer.Ordinal)
+    {
+        "CanOverrideWireColorWithFace",
+        "IsSidePanelVisible",
+        "OverrideFaceColor",
+        "Solar_IsLocalTime",
+        "VisibleGrid",
+        "GridSnap",
+        "MidpointOsnap",
+        "GridSpacing",
+        "GridColor.ALPHA",
+        "GridColor.BLUE",
+        "GridColor.GREEN",
+        "GridColor.RED",
+        "MajorGridColor.ALPHA",
+        "MajorGridColor.BLUE",
+        "MajorGridColor.GREEN",
+        "MajorGridColor.RED",
+    };
+
+    public static (JsonNode? node, int count) MaskVolatileSettings(JsonNode? node)
+    {
+        int count = 0;
+        if (node is null) return (null, 0);
+        Walk(node);
+        return (node, count);
+
+        void Walk(JsonNode n)
+        {
+            if (n is JsonObject obj)
+            {
+                foreach (var kv in obj.ToList())
+                {
+                    if (VolatileSettingFieldNames.Contains(kv.Key))
+                    {
+                        obj[kv.Key] = JsonValue.Create("<VOLATILE>");
+                        count++;
+                    }
+                    else if (kv.Value is JsonObject || kv.Value is JsonArray)
+                    {
+                        Walk(kv.Value);
+                    }
+                }
+            }
+            else if (n is JsonArray arr)
+            {
+                foreach (var item in arr)
+                {
+                    if (item is JsonObject || item is JsonArray) Walk(item);
+                }
+            }
+        }
+    }
+
     /// <summary>
     /// Returns a new JsonNode with object keys sorted recursively. Counts the number of objects sorted.
     /// </summary>