dashboard: list pending builds in the build queue #186

dashboard --json counts pending builds under queues.builds but only lists running ones, so a build sitting outside every runner's -repos scope is invisible except by walking build list per repository. On gitbay.org that is 14 builds across four repositories since 2026-09-03.

List pending builds after the running ones, each with its status and the time it has been waiting, on the JSON, the text dashboard and /admin.