feat: engine-state normalizer profile + sort_array_elements rule (#10)

- Rules.SortArrayElements: sort JSON arrays lexicographically (post-mask_guids order-independence)
- Normalizer output: UnsafeRelaxedJsonEscaping to preserve <GUID>/<TS>/<VOLATILE> tokens
- profiles/engine-state.yaml: normalize_paths + mask_guids + sort_array_elements + round_floats(2dp) + sort_json_keys
- RunnerOptions.SidecarProfile: default "engine-state", overridable via --sidecar-profile
- TestRunner.CaptureAndDiffSidecar: uses SidecarProfile instead of main Profile
- 4 new normalizer tests (136 total)

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

tests/Recordingtest.Normalizer.Tests/RuleTests.cs

@@ -208,4 +208,56 @@ public class RuleTests
             if (Directory.Exists(dir)) Directory.Delete(dir, true);
         }
     }
+
+    // ---- sort_array_elements tests -----------------------------------------
+
+    [Fact]
+    public void SortArrayElements_SortsTopLevelArray()
+    {
+        var node = JsonNode.Parse("[\"banana\",\"apple\",\"cherry\"]");
+        var (n, c) = Rules.SortArrayElements(node);
+        Assert.Equal(1, c);
+        var arr = n!.AsArray();
+        Assert.Equal("apple",  arr[0]!.GetValue<string>());
+        Assert.Equal("banana", arr[1]!.GetValue<string>());
+        Assert.Equal("cherry", arr[2]!.GetValue<string>());
+    }
+
+    [Fact]
+    public void SortArrayElements_NestedArray_SortedIndependently()
+    {
+        var node = JsonNode.Parse("{\"ids\":[\"c\",\"a\",\"b\"]}");
+        var (n, c) = Rules.SortArrayElements(node);
+        Assert.Equal(1, c);
+        var ids = n!["ids"]!.AsArray();
+        Assert.Equal("a", ids[0]!.GetValue<string>());
+        Assert.Equal("b", ids[1]!.GetValue<string>());
+        Assert.Equal("c", ids[2]!.GetValue<string>());
+    }
+
+    [Fact]
+    public void SortArrayElements_AfterGuidMask_OrderIndependent()
+    {
+        // Simulate: selected_ids with two different GUIDs in different orders
+        const string json1 = "{\"selection\":{\"selected_ids\":[\"aaa\",\"bbb\"]}}";
+        const string json2 = "{\"selection\":{\"selected_ids\":[\"bbb\",\"aaa\"]}}";
+        var (n1, _) = Rules.SortArrayElements(JsonNode.Parse(json1));
+        var (n2, _) = Rules.SortArrayElements(JsonNode.Parse(json2));
+        Assert.Equal(
+            n1!["selection"]!["selected_ids"]!.ToJsonString(),
+            n2!["selection"]!["selected_ids"]!.ToJsonString());
+    }
+
+    [Fact]
+    public void Normalize_EngineStateProfile_AppliesAllRules()
+    {
+        // engine-state profile: normalize_paths, mask_guids, sort_array_elements, round_floats, sort_json_keys
+        var guid = "12345678-1234-1234-1234-123456789012";
+        var json = $"{{\"selection\":{{\"selected_ids\":[\"{guid}\"]}},\"camera\":{{\"fov\":45.123456789}}}}";
+        var result = Normalizer.Normalize(json, "engine-state").Output;
+        Assert.Contains("<GUID>", result);
+        Assert.DoesNotContain(guid, result);
+        // fov should be rounded to 2 decimal places
+        Assert.Contains("45.12", result);
+    }
 }