* [#405] added syncToken in calendar params and fetch with sync token
* [#405] changed reload to work with sync-token
* [#405] fixup promise handling, added calendar adding and removing hanlding with refresh
* [#405] fixed event expansion calls
* [#405 & refactor] added helperfunction to get base event uid + refactored synctoken updates management
* [#405] added pMap lib to process event expansion
* [#405] added flag for no synctoken / new synctoken
- Set explicit UTC timezone globally in jest.config.ts and setupTests.ts
- Mock Intl.DateTimeFormat to use UTC by default while preserving prototype
- Replace regex patterns with exact values for declarative assertions
- Remove complex date formatting computations in tests
- Use fixed dates (2025-01-15T10:00:00.000Z) for consistent test results
- Fix EventDisplay.test.tsx to use exact time values instead of regex
lenhanphung