fix(multivalue): NJ-3/NJ-4/NJ-5 review fixes

- NJ-3: widen per-row catch to Exception (an STJ encode failure can't abort startup); drop dead null-guard already excluded by the SQL filter
- NJ-4: capture logger/instanceName in locals for the fire-and-forget normalize continuation (match the sibling pattern in this actor)
- NJ-5: emit a warn-log when a malformed List value is imported verbatim; thread an optional ILogger<BundleImporter> to the sync re-import site

src/ZB.MOM.WW.ScadaBridge.Transport/Serialization/ImportValueNormalizer.cs

@@ -1,3 +1,4 @@
+using Microsoft.Extensions.Logging;
 using ZB.MOM.WW.ScadaBridge.Commons.Types;
 using ZB.MOM.WW.ScadaBridge.Commons.Types.Enums;
 
@@ -29,7 +30,14 @@ internal static class ImportValueNormalizer
     /// <param name="value">The attribute value as carried by the bundle DTO.</param>
     /// <param name="dataType">The attribute's declared data type.</param>
     /// <param name="elementType">The List element type (null for scalars).</param>
-    public static string? NormalizeListValue(string? value, DataType dataType, DataType? elementType)
+    /// <param name="logger">Optional logger; a warning is emitted when a malformed value is left as-is.</param>
+    /// <param name="attributeName">Optional attribute name for the diagnostic message.</param>
+    public static string? NormalizeListValue(
+        string? value,
+        DataType dataType,
+        DataType? elementType,
+        ILogger? logger = null,
+        string? attributeName = null)
     {
         if (dataType != DataType.List || string.IsNullOrEmpty(value))
         {
@@ -41,10 +49,14 @@ internal static class ImportValueNormalizer
             return AttributeValueCodec.Encode(
                 AttributeValueCodec.Decode(value, DataType.List, elementType));
         }
-        catch (FormatException)
+        catch (FormatException ex)
         {
             // Leave malformed values exactly as imported; the DB normalizer is
             // the backstop. Never abort the import for a single bad value.
+            logger?.LogWarning(ex,
+                "Bundle import: could not normalize List value for attribute {Attribute}; " +
+                "importing verbatim (the central DB normalizer is the backstop).",
+                attributeName ?? "(unknown)");
             return value;
         }
     }