feat: auto-convert URL to QR code in PDF export and preview

check_time.py

@@ -0,0 +1,7 @@
+from app import create_app, db
+from app.models import PracticePlan
+app = create_app()
+with app.app_context():
+    plans = PracticePlan.query.order_by(db.desc("created_at")).limit(3).all()
+    for p in plans:
+        print(f"ID:{p.id} | created_at:{p.created_at} | student:{p.student.name if p.student else 'N/A'}")