- Implement processSheetExists function to verify if a specified sheet exists in the workbook.
- Update README.md with usage examples for the new sheet existence check feature.
- Add unit tests for SheetExists functionality to ensure accurate detection of existing and non-existent sheets.
- Implement validateSheetName function to check for invalid characters, empty names, and length restrictions for sheet names.
- Integrate validation into CreateSheet, UpdateSheet, and CopySheet methods to ensure compliance before proceeding with operations.
- Enhance WriteAll method to create a new sheet if it doesn't exist, improving robustness in sheet handling.
- Implement new process handlers for creating, reading, updating, copying, and deleting sheets in Excel files.
- Enhance the Open function to automatically create directories for file paths if they do not exist.
- Update README.md to include detailed documentation and examples for new sheet operations, improving user guidance.
