Add preview functionality for outsource purchase order numbers

- Introduced a new endpoint `/preview-order-no` to generate order numbers based on registered numbering rules without incrementing the sequence.
- Implemented the `previewOrderNo` function in the `outsourcePurchaseController` to handle the logic for generating the preview order number.
- Updated the `outsourcePurchaseRoutes` to include the new route for previewing order numbers.
- Enhanced the `RegistrationModal` component to automatically fill the order number input with the preview value when the modal opens.
- Added a new API function `previewOrderNo` in the frontend to call the backend endpoint.

(TASK:ERP-019)

backend-node/src/controllers/outsourcePurchaseController.ts

@@ -182,6 +182,22 @@ export async function autoProcesses(
   }
 }
 
+// ─────────────────────────────────────────────────────────────────────────────
+// 외주발주번호 미리보기 — 모달 진입 시 input 자동 채움용 (시퀀스 증가 없음)
+// ─────────────────────────────────────────────────────────────────────────────
+export async function previewOrderNo(
+  req: AuthenticatedRequest,
+  res: Response,
+) {
+  try {
+    const companyCode = req.user!.companyCode;
+    const code = await svc.previewOrderNo(companyCode);
+    return ok(res, { generatedCode: code || "" });
+  } catch (e: any) {
+    return fail(res, 500, e?.message || "외주발주번호 미리보기 실패", e);
+  }
+}
+
 // ─────────────────────────────────────────────────────────────────────────────
 // 공정 자재투입(material_input) 자동 채움
 // — 사급자재 체크 시 해당 공정의 자재 목록을 외주발주 자재 형식으로 반환