Vote via email (list) response

I think many projects struggle to collect enough votes. This system can help with that as it allows more easily sharing the vote on additional platforms. On the other hand, for those subscribed to the list already, it doesn't get much lower-friction than hitting 'Reply' with our +1. I believe ATR has a feature where they monitor the list for votes. CAP doesn't do that yet, right? I understand that's a somewhat major feature, but I do think it can be a valuable thing to (perhaps optionally) support.

No files, tests, or entry points are identified. Start by clarifying how CAP should monitor the email list, recognize votes, handle optional support, and connect those votes to the existing voting flow; define acceptance tests for the supported email formats and expected vote outcomes.

Written by the indexing model from the issue text.