refactor: update configuration handling and OpenAI client initialization

src/ui/widgets/MessageCalendar.py

@@ -1,12 +1,14 @@
-from PyQt6 import QtWidgets, QtCore
-from PyQt6.QtCore import QDate
-from PyQt6.QtGui import QColor, QPen
-from src.backend import Database
+import sys
 from typing import Any
+
 import darkdetect
 import loguru
-import sys
+from PyQt6 import QtCore, QtWidgets
+from PyQt6.QtCore import QDate
+from PyQt6.QtGui import QColor, QPen
+
 from src import LOG_DIR
+from src.backend import Database
 
 log = loguru.logger
 log.remove()