bug(wingman): Tab Activity panel renders empty despite active /activity-log data

[hydro13]

Description

The Tab Activity panel in the Wingman sidebar renders completely empty, even though the /activity-log API returns data correctly.

Steps to Reproduce

1. Open Tandem Browser
2. Navigate to a few pages (any tabs)
3. Open the Wingman panel
4. Click "Tab Activity" section

Expected Behavior

List of recent tab events (navigations, page loads, tab switches) rendered in the panel.

Actual Behavior

Panel is blank / empty. No entries shown.

Investigation

Verified via API: GET /activity-log returns valid entries (43 entries confirmed during testing). Backend is working correctly. Issue is isolated to the UI rendering layer of the Wingman panel.

Environment

• Tandem Browser (latest main)
• macOS

Notes

The activity log previously worked as a live audit trail / tab activity overview. This is a regression.