Add comprehensive timezone fallback support and update tests #54

Job	Run time
Test Python 3.13 on windows-latest	1m 8s
Test Python 3.12 on ubuntu-latest	37s
Build for Python ${{ matrix.python-version }} on ${{ matrix.os }}	0s
Test Python 3.13 on ubuntu-latest	45s
Test Python 3.12 on macos-latest	2m 44s
Test Python 3.13 on macos-latest	2m 43s
Test Python 3.12 on windows-latest	1m 12s
Create Release	0s
Publish to PyPI	0s
	9m 9s

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