The concurrency limit moved to executor.maxConcurrent without an alias, so
the old key binds a scalar where a build definition belongs and failed the
whole configuration. But that configuration is committed in the watched
repository, and a repository's master is not always changeable right away —
an installation must not be stuck on a key it is meant to forget.
A `builds` entry that is not a mapping is now dropped with a warning (once
per key, the config is loaded every poll cycle), naming executor.maxConcurrent
for the key that moved.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
