docs(csharp): refresh stale @dbColumn comment to @column in CSharpNaming

Minor finding from the C# source-v2 final reviewer: the comment in CSharpNaming.Column()
described the override attr as @dbColumn, but the rename to @column landed in commit 1727b33.
Runtime behavior is correct; this was a comment-only staleness.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: dmealing

server/csharp/MetaObjects.Codegen/CSharpNaming.cs

@@ -57,7 +57,7 @@ public static string Pascal(string name) =>
     public static string Table(MetaObject entity) => entity.DbTable ?? entity.Name;
 
     /// <summary>
-    /// The DB column name for a field: the <c>@dbColumn</c> override, else the raw
+    /// The DB column name for a field: the <c>@column</c> override, else the raw
     /// field name. Shared so the schema DDL and the [Column] annotation agree.
     /// </summary>
     public static string Column(MetaField field) => field.DbColumn ?? field.Name;