Votes should not close automatically on reaching the deadline

The deadline for a vote should not be a cut-off for participation in voting.
Instead it should be a minimum that the vot will be held open, as is done currently for release candidates.

It should be up to the vote controller to decide when to close the vote.

Trace where vote deadlines trigger automatic closure, then compare that flow with the existing release-candidate behavior described in the issue. Identify how the vote controller currently decides closure; done means the deadline acts as a minimum open period and only the controller closes the vote.

Written by the indexing model from the issue text.