refactor(main): rely on lifespan for db init (SP5)

backend/src/cyclone/__main__.py

@@ -27,10 +27,8 @@ def main() -> None:
         ]
         if reload:
             sys.argv.append("--reload")
-        # Initialize the DB (engine, migrations, schema) before the app
-        # boots so the first request hits a populated database.
-        from cyclone import db
-        db.init_db()
+        # DB + EventBus are initialized by the FastAPI lifespan handler
+        # (cyclone.api:lifespan); no explicit pre-init is needed here.
         import uvicorn
 
         uvicorn.main()