Also reduces last time_us discard window down to 2 days.

Restyle commits in repo index and implement a separate commits page with pagination.

I'm bfg'ing this.

Custom lexicon for issues, issue state (open, closed) and issue comments.

The case with issue_at is a bit weird since we have a circular dependency: the issue record requires the issue_id, and the issue entry in the db requires the issue_at.

To resolve this we write to the db without the issue_at, fetch the issue_id, create the issue record on the PDS, and then update the issue_at (with SetIssueAt). It's not great, but whatever.

also fix nix builds

some links still need to be stuffed into a dropdown