refactor: Enhance unique constraint validation across data operations

- Integrated `TableManagementService` to validate unique constraints before insert, update, and upsert actions in various controllers, including `dataflowExecutionController`, `dynamicFormController`, and `tableManagementController`.
- Improved error handling in `errorHandler` to provide detailed messages indicating which field has a unique constraint violation.
- Updated the `formatPgError` utility to extract and display specific column labels for unique constraint violations, enhancing user feedback.
- Adjusted the table schema retrieval to include company-specific nullable and unique constraints, ensuring accurate representation of database rules.

These changes improve data integrity by preventing duplicate entries and enhance user experience through clearer error messages related to unique constraints.

backend-node/src/middleware/errorHandler.ts

@@ -41,7 +41,18 @@ export const errorHandler = (
     // PostgreSQL 에러 코드 참조: https://www.postgresql.org/docs/current/errcodes-appendix.html
     if (pgError.code === "23505") {
       // unique_violation
-      error = new AppError("중복된 데이터가 존재합니다.", 400);
+      const constraint = pgError.constraint || "";
+      const tbl = pgError.table || "";
+      let col = "";
+      if (constraint && tbl) {
+        const prefix = `${tbl}_`;
+        const suffix = "_key";
+        if (constraint.startsWith(prefix) && constraint.endsWith(suffix)) {
+          col = constraint.slice(prefix.length, -suffix.length);
+        }
+      }
+      const detail = col ? ` [${col}]` : "";
+      error = new AppError(`중복된 데이터가 존재합니다.${detail}`, 400);
     } else if (pgError.code === "23503") {
       // foreign_key_violation
       error = new AppError("참조 무결성 제약 조건 위반입니다.", 400);