refactor(config): reorganize config.toml into sections

- Move all settings into [general], [dock], [panel], [switcher], [notification]
- Remove [desktop_widgets] section, move items to panel/general
- Add dot notation support to config service for nested keys
- Update all config references across codebase

src/main.py

@@ -45,7 +45,7 @@ def setup_logger():
     ]:
         logger.disable(log)
 
-    _debug = config().get("debug", False)
+    _debug = config().get("general.debug", False)
     if not _debug:
         logger.disable("modus_plugin_builtin_emoji")
     else: