TUI session picker sorts by day instead of actual timestamp #24727

Bug Description

The TUI session picker groups sessions by update day and sorts within each day by creation time, rather than by the actual time.updated timestamp.

Steps to Reproduce

1. Create multiple sessions
2. Update a session that was created earlier in the day
3. Open the session picker
4. Observe that the recently-updated session does not appear at the top

Expected Behavior

Sessions should sort by actual time.updated timestamp (most recent first), matching the server-side Session.list() ordering.

Actual Behavior

Sessions are grouped by calendar day (setHours(0,0,0,0)), and within the same day they sort by creation time. The picker footer shows correct timestamps, but the sort order does not match them.

UX Impact

When you have multiple sessions updated today, they sort by creation order instead of most recent activity. This means switching to your most recently used session requires navigating past inactive conversations first.

Related

• Complements GET /session: Add ORDER BY time_updated DESC to Session.list() for deterministic ordering and correct limit behavior #13569 (server-side ORDER BY time_updated DESC)
• Complements feat(tui): add session_list_limit for session picker #6138 (session_list_limit)