fix: 修复 SQLite 连接复用导致数据库不可用

app/db.py

@@ -5,6 +5,7 @@ from datetime import UTC, datetime
 
 from sqlalchemy import Engine, create_engine, event
 from sqlalchemy.orm import DeclarativeBase, Session, sessionmaker
+from sqlalchemy.pool import NullPool
 
 from app.config import get_settings
 
@@ -20,7 +21,10 @@ def create_sqlite_engine(database_url: str):
             db_path.parent.mkdir(parents=True, exist_ok=True)
 
     connect_args = {"check_same_thread": False, "timeout": 10}
-    engine = create_engine(database_url, connect_args=connect_args)
+    engine_kwargs = {"connect_args": connect_args}
+    if database_url.startswith("sqlite:///") and database_url != "sqlite:///:memory:":
+        engine_kwargs["poolclass"] = NullPool
+    engine = create_engine(database_url, **engine_kwargs)
     engine.dialect.connect_args = connect_args
 
     @event.listens_for(engine, "connect")