- Implemented `SetHyperlink` method to allow adding hyperlinks to cells with optional tooltips.
- Integrated OpenXML `Hyperlink` and `Hyperlinks` elements to manage cell hyperlinks.
- Added `GetWorksheetPart` helper to locate the parent `WorksheetPart` for a cell.
- Included XML documentation for `SetHyperlink` and `GetWorksheetPart` methods for API clarity.
- Ensured compatibility with the existing `Cell` class and OpenXML SDK conventions.

Example Usage:
- Add a hyperlink to a cell:
  cell.PutValue("Click Here");
  cell.SetHyperlink("https://example.com", "Visit Example Website");