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/008_create_update_triggers.sql

@@ -0,0 +1,36 @@
+-- 008_create_update_triggers.sql
+-- 작업보고서 변경 시 월별 집계 자동 업데이트 트리거
+
+DELIMITER $$
+
+-- 작업보고서 INSERT 트리거
+CREATE OR REPLACE TRIGGER tr_daily_work_reports_insert
+AFTER INSERT ON daily_work_reports
+FOR EACH ROW
+BEGIN
+    CALL UpdateMonthlyWorkerStatus(NEW.report_date, NEW.worker_id);
+END$$
+
+-- 작업보고서 UPDATE 트리거
+CREATE OR REPLACE TRIGGER tr_daily_work_reports_update
+AFTER UPDATE ON daily_work_reports
+FOR EACH ROW
+BEGIN
+    -- 기존 날짜 업데이트
+    CALL UpdateMonthlyWorkerStatus(OLD.report_date, OLD.worker_id);
+    
+    -- 새 날짜가 다르면 새 날짜도 업데이트
+    IF OLD.report_date != NEW.report_date OR OLD.worker_id != NEW.worker_id THEN
+        CALL UpdateMonthlyWorkerStatus(NEW.report_date, NEW.worker_id);
+    END IF;
+END$$
+
+-- 작업보고서 DELETE 트리거
+CREATE OR REPLACE TRIGGER tr_daily_work_reports_delete
+AFTER DELETE ON daily_work_reports
+FOR EACH ROW
+BEGIN
+    CALL UpdateMonthlyWorkerStatus(OLD.report_date, OLD.worker_id);
+END$$
+
+DELIMITER ;