refactor(app): restructure project to avoid circular imports

app/startup/lifecycle.py

@@ -0,0 +1,19 @@
+from contextlib import asynccontextmanager
+
+from fastapi import FastAPI
+
+from app.startup.module_initializer import start_modules, shutdown_modules
+from app.startup.routers import init_routers
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """
+    定义应用的生命周期事件
+    """
+    print("Starting up...")
+    start_modules(app)
+    init_routers(app)
+    yield
+    print("Shutting down...")
+    shutdown_modules(app)