refactor: replace deprecated on_event with lifespan context manager

main.py

@@ -17,31 +17,43 @@
 """
 Main entry point for Sugar-AI application.
 """
-
 import uvicorn
 import logging
-from sqlalchemy.orm import Session
 import os
-
-from app import create_app
+from contextlib import asynccontextmanager
+from fastapi import FastAPI
 from app.database import get_db
 from app.auth import sync_env_keys_to_db
 from app.config import settings
+from app import create_app
 
-# setup logging
+# Setup logging
 logger = logging.getLogger("sugar-ai")
 
-app = create_app()
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """
+    Handles the startup and shutdown lifecycle of the application.
+    Replaces the deprecated @app.on_event("startup") and "shutdown".
+    """
+    # --- Startup Logic ---
+    try:
+        db = next(get_db())
+        sync_env_keys_to_db(db)
+        logger.info(f"Starting Sugar-AI with model: {settings.DEFAULT_MODEL}")
+    except Exception as e:
+        logger.error(f"Failed to initialize app during startup: {e}")
+        raise e
+
+    yield 
+
+    # --- Shutdown Logic ---
+    logger.info("Shutting down Sugar-AI...")
 
-@app.on_event("startup")
-async def startup_event():
-    """Initialize data on app startup"""
-    db = next(get_db())
-    sync_env_keys_to_db(db)
-    logger.info(f"Starting Sugar-AI with model: {settings.DEFAULT_MODEL}")
+app = create_app()
+app.router.lifespan_context = lifespan
 
 if __name__ == "__main__":
     port = int(os.getenv("PORT", 8000))
     logger.info(f"Starting Sugar-AI on port {port}")
-    uvicorn.run(app, host="0.0.0.0", port=port)
-
+    uvicorn.run(app, host="0.0.0.0", port=port)