fix: preserve legacy settings decimal semantics

Plant3D2026/P_Rec_Annot/src/PRecAnnot.Core/ProductionSettingsContract.cs

@@ -37,7 +37,7 @@ public sealed record ProductionSettingsContract(
         var setLayer = root.Element("SetLayer")?.Attribute("name")?.Value;
         if (string.IsNullOrWhiteSpace(setLayer)) throw Invalid("SetLayer.name");
         var plusLength = root.Element("PlusLengthNO")?.Attribute("value")?.Value;
-        double? parsedPlusLength = double.TryParse(plusLength, NumberStyles.Float, CultureInfo.InvariantCulture, out var plus) ? plus : null;
+        double? parsedPlusLength = TryParseLegacyNumber(plusLength, out var plus) ? plus : null;
         return new(
             copy,
             layers,
@@ -55,6 +55,11 @@ public sealed record ProductionSettingsContract(
     }
 
     private static int? ParseInt(XElement value, string name) => int.TryParse(value.Attribute(name)?.Value, NumberStyles.Integer, CultureInfo.InvariantCulture, out var parsed) ? parsed : null;
+    private static bool TryParseLegacyNumber(string? value, out double parsed)
+    {
+        if (double.TryParse(value, NumberStyles.Float, CultureInfo.InvariantCulture, out parsed)) return true;
+        return double.TryParse(value?.Replace(',', '.'), NumberStyles.Float, CultureInfo.InvariantCulture, out parsed);
+    }
     private static string Required(XElement? value, string name, bool allowEmpty = false) => value?.Attribute(name) is { Value: var result } && (allowEmpty || !string.IsNullOrWhiteSpace(result)) ? result : throw Invalid(name);
     private static InvalidDataException Invalid(string field) => new("PRODUCTION_SETTINGS_INVALID:" + field);
 }

Plant3D2026/P_Rec_Annot/tests/PRecAnnot.Core.Tests/ProductionSettingsContractTests.cs

@@ -35,4 +35,12 @@ public sealed class ProductionSettingsContractTests
         var exception = Assert.Throws<InvalidDataException>(() => ProductionSettingsContract.Parse(xml));
         Assert.Equal("PRODUCTION_SETTINGS_INVALID:layer", exception.Message);
     }
+
+    [Fact]
+    public void ParsesLegacyCommaDecimalPlusLength()
+    {
+        const string xml = "<Main><CopyMissingObjects/><LayersSetup/><Annotations layer='TEXT' textstyle='GOSTC' multileaderstyle='PXP'/><LinenumberConnections polylinelayer='AXIS' textlayer='TEXT' textstyle='GOSTC'/><Elevations layer='THIN' textstyle='GOSTC'/><SetLayer name='AXIS'/><PlusLengthNO value='1,5'/></Main>";
+        var result = ProductionSettingsContract.Parse(xml);
+        Assert.Equal(1.5, result.FixedSupportPlusLength);
+    }
 }