feat: Introduce knex for database migrations

- Adds knex.js to manage database schema changes systematically.
- Creates an initial migration file based on `hyungi_schema_v2.sql` to represent the current database state.
- Adds npm scripts (`db:migrate`, `db:rollback`, etc.) for easy execution of migration tasks.
- Archives legacy SQL files and old migration scripts into the `db_archive/` directory to prevent confusion and clean up the project structure.

api.hyungi.net/db_archive/migrations_backup/update_hyungi_system_role.sql

@@ -0,0 +1,45 @@
+-- hyungi 계정을 시스템 권한으로 업데이트
+-- 실행 날짜: 2025-01-XX
+
+-- hyungi 계정의 role을 system으로 변경
+UPDATE Users 
+SET 
+    role = 'system',
+    access_level = 'system',
+    name = '시스템 관리자',
+    updated_at = NOW()
+WHERE username = 'hyungi';
+
+-- 변경 결과 확인
+SELECT 
+    user_id, 
+    username, 
+    name, 
+    role, 
+    access_level, 
+    is_active,
+    updated_at
+FROM Users 
+WHERE username = 'hyungi';
+
+-- 시스템 권한 확인을 위한 쿼리
+SELECT 
+    username,
+    name,
+    role,
+    access_level,
+    CASE 
+        WHEN role = 'system' THEN '✅ 시스템 관리자'
+        WHEN role = 'admin' THEN '🔧 관리자'
+        WHEN role = 'leader' THEN '👨‍🏫 그룹장'
+        ELSE '👤 일반 사용자'
+    END as permission_level
+FROM Users 
+ORDER BY 
+    CASE role
+        WHEN 'system' THEN 1
+        WHEN 'admin' THEN 2
+        WHEN 'leader' THEN 3
+        ELSE 4
+    END,
+    username;