review try-out: author the PR branch at the account's noreply address

The commit author's email was the forge account's own address, read with
the site-admin token, which put an email the account may keep private
into the target repo's history. It is now the address Forgejo itself
uses for such an account's web commits, `<lowercased login>@<NO_REPLY_ADDRESS>`
(models/user/user.go GetPlaceholderEmail). NO_REPLY_ADDRESS defaults to
`noreply.<DOMAIN>` (modules/setting/service.go) and the forge module
leaves it unset, with DOMAIN set from services.hyperhive.swarm.forge.domain,
the same option SWARM_CONTROLLER_FORGE_URL is built from; so the domain is
that URL's host. The account is still read, to refuse a user with no
forge account, but its email no longer is.

Refs #5259

docs/swarm/review-classifier.md

@@ -484,8 +484,11 @@ branch, where you log in as usual and open the PR yourself.
 - **The author** is the forge account named like your swarm UI login. A forge
   account made by an SSO login carries the SSO username, so it's yours once
   you've logged in to the forge. The commit carries its full name, or the
-  login when it has none, and its email. The committer is the service
-  account.
+  login when it has none, and its noreply address,
+  `<login, lowercased>@noreply.<forge domain>`. It's the address the forge
+  itself uses for an account that keeps its email private, so the commit
+  links to your account and your email stays out of the repo's history. The
+  committer is the service account.
 - **The token** is the service account's own, read from the store for each
   push (see [The service account](#the-service-account)), so the account
   needs **write** access to the repo.