Bug: shop signs stop working after restart

We tried three versions of this before settling on the one here. The numbers below come from the last thirty days.

We tried three versions of this before settling on the one here. We will keep the old behaviour for another season.

This has been on the test server for two weeks. The full list is below, with the dates for each step. We tried three versions of this before settling on the one here. This one has been asked for often enough that we finally built it.