## Summary
- Fix account switching bug where new users couldn't switch accounts properly
- Update `active_account_user` method to handle NULL `active_at` values correctly using `NULLS LAST` sorting
- Add comprehensive specs to test the NULL handling behavior
## Problem
When users were added to new accounts, the `active_at` field was NULL. The existing `ORDER BY active_at DESC` had undefined behavior for NULL values, causing:
- Mobile apps to receive wrong `account_id` from `/profile` API
- Account switching to fail until multiple attempts "fixed" it temporarily
- Issue recurring whenever new accounts were added
## Solution
- Updated `active_account_user` method in `UserAttributeHelpers` to use `NULLS LAST` sorting
- This ensures accounts with actual timestamps are prioritized over NULL values
- Added specs covering normal sorting, NULL handling, and edge cases
Muhsin
28969deb01