feat(db): migration for ElementDataType + widen attribute Value to nvarchar(max) (idempotent)

src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Configurations/InstanceConfiguration.cs

@@ -99,8 +99,12 @@ public class InstanceAttributeOverrideConfiguration : IEntityTypeConfiguration<I
             .IsRequired()
             .HasMaxLength(200);
 
-        builder.Property(o => o.OverrideValue)
-            .HasMaxLength(4000);
+        // nvarchar(max): List attribute values (JSON arrays) can exceed 4000 chars.
+        builder.Property(o => o.OverrideValue);
+
+        builder.Property(o => o.ElementDataType)
+            .HasConversion<string>()
+            .HasMaxLength(50);
 
         builder.HasIndex(o => new { o.InstanceId, o.AttributeName }).IsUnique();
     }

src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Configurations/TemplateConfiguration.cs

@@ -108,8 +108,8 @@ public class TemplateAttributeConfiguration : IEntityTypeConfiguration<TemplateA
             .IsRequired()
             .HasMaxLength(200);
 
-        builder.Property(a => a.Value)
-            .HasMaxLength(4000);
+        // nvarchar(max): List attribute values (JSON arrays) can exceed 4000 chars.
+        builder.Property(a => a.Value);
 
         builder.Property(a => a.Description)
             .HasMaxLength(2000);
@@ -121,6 +121,10 @@ public class TemplateAttributeConfiguration : IEntityTypeConfiguration<TemplateA
             .HasConversion<string>()
             .HasMaxLength(50);
 
+        builder.Property(a => a.ElementDataType)
+            .HasConversion<string>()
+            .HasMaxLength(50);
+
         builder.HasIndex(a => new { a.TemplateId, a.Name }).IsUnique();
     }
 }