Implement Comma Value Resolution in Entity Join Service

- Added a new method `resolveCommaValues` in `EntityJoinService` to handle comma-separated values for entity joins, allowing for individual code resolution and label conversion.
- Integrated the new method into `TableManagementService` to process data after executing join queries.
- Enhanced the `DynamicComponentRenderer` to maintain entity label columns based on existing configurations.

Made-with: Cursor

frontend/lib/registry/DynamicComponentRenderer.tsx

@@ -102,12 +102,16 @@ function mergeColumnMeta(tableName: string | undefined, columnName: string | und
   if (dbInputType === "entity") {
     const refTable = meta.reference_table || meta.referenceTable;
     const refColumn = meta.reference_column || meta.referenceColumn;
-    const displayCol = meta.display_column || meta.displayColumn;
+    const rawDisplayCol = meta.display_column || meta.displayColumn;
+    const displayCol = rawDisplayCol && rawDisplayCol !== "none" && rawDisplayCol !== "" ? rawDisplayCol : undefined;
     if (refTable) {
       merged.source = "entity";
       merged.entityTable = refTable;
       merged.entityValueColumn = refColumn || "id";
-      merged.entityLabelColumn = displayCol || "name";
+      // 화면 설정에 이미 entityLabelColumn이 있으면 유지, 없으면 DB 값 또는 기본값 사용
+      if (!merged.entityLabelColumn) {
+        merged.entityLabelColumn = displayCol || "name";
+      }
       merged.fieldType = "entity";
       merged.inputType = "entity";
     }