Initiated the process of refactoring the monolithic `work-report-calendar.js` file as outlined in the Phase 2 frontend modernization plan.
- Created `CalendarAPI.js` to encapsulate all API calls related to the calendar, centralizing data fetching logic.
- Created `CalendarState.js` to manage the component's state, removing global variables from the main script.
- Refactored `work-report-calendar.js` to use the new state and API modules.
- Refactored `manage-project.js` to use the existing global API helpers, providing a consistent example for API usage.
