[RGAA 5.7] Data table cells not associated with headers

[jbpenrath]

Bug Report

Problematic behavior
In the signature list table, header cells (<th>) do not have scope attributes, preventing assistive technologies from properly associating data cells with their column headers.

Expected behavior/code
Each <th> should carry scope="col" so that screen readers can announce column headers when navigating table cells.

Steps to Reproduce

1. Navigate to the signature management page
2. Open the signature list table
3. Use a screen reader to navigate through table cells — headers are not announced

Environment

• RGAA Criterion: 5.7
• Severity: 🟡 Minor

Possible Solution
Add scope="col" on each <th> element table.

Additional context/Screenshots
RGAA reference: Criterion 5.7