feat(tkuser): Sprint 001 Section A — 연차/휴가 백엔드 전환 (DB + API)

workers/vacation_balance_details → sso_users/sp_vacation_balances 기반 전환.
부서장 설정, 승인권한 CRUD, vacation_settings 테이블, 장기근속 자동부여,
startup migration 추가.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

user-management/api/controllers/departmentController.js

@@ -1,7 +1,7 @@
 /**
  * Department Controller
  *
- * 부서 CRUD
+ * 부서 CRUD + 승인권한 관리
  */
 
 const departmentModel = require('../models/departmentModel');
@@ -63,4 +63,49 @@ async function remove(req, res, next) {
   }
 }
 
-module.exports = { getAll, getById, create, update, remove };
+/* ===== 승인권한 (Approval Authority) ===== */
+
+async function getApprovalAuthorities(req, res, next) {
+  try {
+    const departmentId = parseInt(req.params.id);
+    const data = await departmentModel.getApprovalAuthorities(departmentId);
+    res.json({ success: true, data });
+  } catch (err) {
+    next(err);
+  }
+}
+
+async function createApprovalAuthority(req, res, next) {
+  try {
+    const departmentId = parseInt(req.params.id);
+    const { approval_type, approver_user_id } = req.body;
+    if (!approval_type || !approver_user_id) {
+      return res.status(400).json({ success: false, error: '승인유형과 승인자는 필수입니다' });
+    }
+    const data = await departmentModel.createApprovalAuthority({
+      department_id: departmentId,
+      ...req.body
+    });
+    res.status(201).json({ success: true, data });
+  } catch (err) {
+    if (err.code === 'ER_DUP_ENTRY') {
+      return res.status(409).json({ success: false, error: '이미 등록된 승인권한입니다' });
+    }
+    next(err);
+  }
+}
+
+async function deleteApprovalAuthority(req, res, next) {
+  try {
+    const authId = parseInt(req.params.authId);
+    await departmentModel.deleteApprovalAuthority(authId);
+    res.json({ success: true, message: '승인권한이 삭제되었습니다' });
+  } catch (err) {
+    next(err);
+  }
+}
+
+module.exports = {
+  getAll, getById, create, update, remove,
+  getApprovalAuthorities, createApprovalAuthority, deleteApprovalAuthority
+};