feat: Implement application preferences with JSON persistence

- Added preferences management in `preferences.py` with functions to load, save, get, set, and reset preferences.
- Introduced a configuration directory structure based on the operating system.
- Integrated preferences into the settings window, allowing users to reset settings and manage window geometry.
- Enhanced `search_filter.py` to support flexible date column names and improved filtering logic.
- Updated `settings_window.py` to include options for managing backup and configuration folder paths.
- Introduced an `UndoManager` class to handle undo actions for add/update/delete operations.
- Improved UIManager to support sorting in tree views and added a toast notification feature.

src/init.py

@@ -1,31 +1,15 @@
-import os
+"""App initialization: configure the root logger once per process.
 
-from constants import LOG_CLEAR, LOG_LEVEL, LOG_PATH
+We delegate directory creation and file clearing to the logger utility,
+which honors LOG_PATH, LOG_LEVEL, and LOG_CLEAR.
+"""
+
+from __future__ import annotations
+
+from constants import LOG_LEVEL
 from logger import init_logger
 
-if not os.path.exists(LOG_PATH):
-    try:
-        os.mkdir(LOG_PATH)
-        print(LOG_PATH)
-    except Exception as e:
-        print(e)
-
-log_files = (
-    f"{LOG_PATH}/thechart.log",
-    f"{LOG_PATH}/thechart.warning.log",
-    f"{LOG_PATH}/thechart.error.log",
-)
-
-testing_mode = LOG_LEVEL == "DEBUG"
+testing_mode: bool = LOG_LEVEL == "DEBUG"
 
+# Expose a module-level logger for imports like `from init import logger`
 logger = init_logger(__name__, testing_mode=testing_mode)
-
-if LOG_CLEAR == "True":
-    try:
-        for log_file in log_files:
-            if os.path.exists(log_file):
-                with open(log_file, "r+") as t:
-                    t.truncate(0)
-    except Exception as e:
-        logger.error(e)
-        raise