Describe the bug
On the Discussion Forum statistics page, clicking the sortable column headers (User, Total Posts (not deleted), Total Threads, Total Deleted Posts, and Total Upducks) can cause the header labels to render as escaped HTML text (for example, <a href="#">User</a>).

Expected behavior
The stats table headers should remain properly rendered as normal text/sort labels after being clicked. No escaped HTML should appear, and sorting should continue to behave normally.

To Reproduce
Steps to reproduce the behavior:

1. Go to the Discussion Forum statistics page (/forum/stats).
2. Click any sortable column header:
   • User
   • Total Posts (not deleted)
   • Total Threads
   • Total Deleted Posts
   • Total Upducks
3. Observe that the header text may change into escaped HTML text such as <a href="#">...</a>.

Configuration

• OS: macOS
• Browser: Chrome

Screenshots
A screen recording is attached showing:

• normal stats table behavior initially
• escaped HTML appearing in the header labels after clicking a sortable column header

Additional context
This appears to be caused by a combination of:

• invalid table structure in the stats page (e.g., multiple <tbody> elements and missing <thead>)
• sortable headers implemented using nested <a href="#">...</a> inside <th>
• JavaScript relying on header HTML (.html()) during sorting