Hyperlink tooltip attribute not parsed from XML on read

[wolfiesch]

Description

When reading an .xlsx file that contains hyperlinks with tooltip attributes, the tooltip value is not parsed from the XML. The get_tooltip() method returns an empty string even though the tooltip was set in Excel.

Steps to Reproduce

1. Create an .xlsx file in Excel with a hyperlink that has a tooltip (Insert > Hyperlink > ScreenTip)
2. Read the file with umya-spreadsheet
3. Access the hyperlink via cell.get_hyperlink().get_tooltip()

Expected Behavior

get_tooltip() returns the tooltip string (e.g., "Click to visit website")

Actual Behavior

get_tooltip() returns an empty string.

Analysis

Looking at the XML parsing path in worksheet.rs, the hyperlink deserialization reads ref, location, and r:id attributes but appears to skip the tooltip attribute from the <hyperlink> element. The OPC markup is:

<hyperlink ref="A1" r:id="rId1" tooltip="Click to visit website"/>

The tooltip attribute needs to be captured during XML deserialization.

Additional Issue: URL XML Entity Encoding

When a URL contains & characters, they are XML-escaped to & in the .xlsx XML. On read, umya does not unescape these entities, so get_url() returns URLs with literal & instead of &.

Environment

• umya-spreadsheet 2.2.x
• Discovered via ExcelBench fidelity testing