Refactor database message handling to support multiple messages and enhance type hints across various classes

src/ui/widgets/MessageCalendar.py

@@ -2,6 +2,7 @@ from PyQt6 import QtWidgets, QtCore
 from PyQt6.QtCore import QDate
 from PyQt6.QtGui import QColor, QPen
 from src.backend import Database
+from typing import Any
 import darkdetect
 import loguru
 import sys
@@ -37,7 +38,7 @@ class MessageCalendar(QtWidgets.QCalendarWidget):
         self.messages.remove(message)
         self.updateCells()
 
-    def setMessages(self, messages):
+    def setMessages(self, messages: list[dict[str, Any]]):
         # remove all drawn circles
 
         for message in messages: