feat: add MONGO_URI to environment variable setup in build workflow

backend/db/mongo_client.py

@@ -22,6 +22,10 @@ _mongo_client = None
 def _create_mongo_client():
     """Build a fail-fast MongoClient from environment variables."""
     uri = os.environ.get('MONGO_URI')
+    #log the MONGO_URI for debugging purposes, I will change it later so it doesn't log the password
+    print(f"Using MONGO_URI: {uri}")
+
+
     if not uri:
         raise RuntimeError(
             'MONGO_URI environment variable is required when USE_MONGODB=true.'