* feat: clearOverride also clears election exclusions

clearOverride() now calls clearExclusions() to lift all
excludeFromElection() cooldowns when reverting to natural
cascade logic. This fixes the E2E g12 re-election test:
after an override cycle the original hub was still excluded
(~60s cooldown) so a different node won re-election.

Also adds clearExclusions() as public API.

* Increase version