移除示例项目初始化并修复前后端稳定性问题

backend/app/main.py

@@ -15,7 +15,6 @@ from app.core.exceptions import register_exception_handlers
 from app.crud.user import ensure_admin_exists
 from app.db.base import Base
 from app.db.session import SessionLocal, engine
-from app.services.fee_seed import seed_demo_fees
 from app.services.visit_scheduler import run_daily_lost_visit_job
 
 logger = logging.getLogger("ctms.setup_config")
@@ -38,7 +37,6 @@ async def lifespan(_: FastAPI):
             await conn.run_sync(Base.metadata.create_all)
         async with SessionLocal() as session:
             await ensure_admin_exists(session)
-            await seed_demo_fees(session)
     yield
     stop_event.set()
     await scheduler_task