Follow-ups from the review of #5142.
A `Done` answer with fewer or more rows than the classifications sent, or
none, now posts the no-verdict comment instead of the classifier's overall
verdict, so a short answer can't approve.
Requests are accepted per repo, PR and head into a set bounded at the two
running plus eight waiting. A request for a key already running or waiting
starts nothing and logs at info; a request with every place taken starts no
run and posts a no-verdict comment saying so. Before, every delivery spawned
a task waiting on the semaphore, so toggling the review request queued one
paid run per toggle.
Table cells get a zero-width space after `#`, `!`, `://` and `www.`, so a
model's reason can't render an issue or PR reference or a bare URL as a link.
The secret publisher's policy denies the classifier's forge token leaf, the
way #5139 denied Grafana's admin password, with a module-eval-bao-grants arm
pinning it. The controller posts reviews with whatever token is there, so a
publisher write picked the account reviews come from.
Closes#5143, part of #5096.