feat(lists): assign a colour to a sidebar folder

Tints the folder name and its guide line; picked from a swatch row in the folder settings.

src/ClaudeDo.Data/Configuration/ListFolderEntityConfiguration.cs

@@ -15,6 +15,7 @@ public class ListFolderEntityConfiguration : IEntityTypeConfiguration<ListFolder
         builder.Property(f => f.Name).HasColumnName("name").IsRequired();
         builder.Property(f => f.CreatedAt).HasColumnName("created_at").IsRequired();
         builder.Property(f => f.Icon).HasColumnName("icon");
+        builder.Property(f => f.Color).HasColumnName("color");
         builder.Property(f => f.SortOrder).HasColumnName("sort_order").IsRequired().HasDefaultValue(0);
         builder.Property(f => f.IsCollapsed).HasColumnName("is_collapsed").IsRequired().HasDefaultValue(false);
         builder.Property(f => f.ParentFolderId).HasColumnName("parent_folder_id");