Automatic logout after timeout

**User Story**
As any user in SIMS, if the "confirm extend time" modal pops up and counts down to 0 I should be automatically logged out and the page refreshed.

**Current Behaviour**
The timeout popup will eventually countdown to 0 and then go into a negative number. Pressing "yes" at this point keeps you on the same screen and doesn't give you any indication that you are no longer validly signed in.

**Acceptance Criteria**
- [ ] After timeout countdown reaches 0, user should be automatically logged out and the page refreshed so they can easily re-login.

No files or tests are named. Start by locating the SIMS timeout confirmation modal and its countdown handling, then reproduce the countdown reaching zero. Done means the user is logged out and the page refreshes at zero, allowing an easy re-login.

Written by the indexing model from the issue text.