Improves drag and drop functionality by refactoring column detection to use column bounds instead of dates.
This change enhances the accuracy and efficiency of determining the target column during drag operations.
It also removes redundant code and simplifies the logic in both the DragDropManager and AllDayManager.
Streamlines calendar configuration by adopting a singleton pattern for consistent access and simplifies event handling.
- Removes direct `CalendarConfig` dependency injection in favor of the `calendarConfig` singleton, reducing code complexity.
- Replaces specific event emissions for grid, date, and resource settings updates with a general `REFRESH_REQUESTED` event.
- Updates event names to be more descriptive and consistent ("NAVIGATION_COMPLETED", "PERIOD_INFO_UPDATE").
- Removes the need to pass the calendar config to renderers since it is now a singleton.
This improves code maintainability and simplifies the event emission process.
Improves drag and drop performance by caching DOM elements and consolidating position calculations.
This reduces redundant DOM queries and optimizes event handling for smoother user interaction.
Also leverages `DateCalculator` for date/time conversions.
