tasks: no visual indication when github auth expires #20755

Problem

When external authentication (e.g., GitHub OAuth) expires, tasks fail silently on the tasks page with no visual indication of the root cause. Users must navigate away from the tasks page to the workspace page to discover that authentication has expired and needs to be renewed.

Here's a little context, but not 100% related -- https://codercom.slack.com/archives/C04TUUQ0L4S/p1762194760257209

Current Behavior

• Tasks page: No visual warning or indicator when external auth expires - tasks simply fail without clear explanation
• Workspace page: Shows visual indicators for auth issues (this works correctly)
• User workflow: Users must leave the tasks page → navigate to workspace page → see auth expired warning → re-authenticate

Expected Behavior

The tasks page should display the same external auth status indicators that the workspace page provides, so users can:

1. Immediately see when external auth has expired
2. Re-authenticate without leaving the tasks page
3. Understand why their tasks are failing without detective work

Impact

• Poor user experience with mysterious task failures
• Wasted time debugging auth issues that should be immediately visible
• Inconsistent UX between workspace page (shows auth status) and tasks page (doesn't)