Agent Draft Counts

True per-agent draft totals for the agents list and queue tab badges, keyed by agent id. The per-agent drafts LIST caps at the 500 newest rows across all statuses, so any count derived from it silently understates a 1000+ draft agent (the newest rows are mostly sent). This aggregates over everything: status counts straight from GROUP BY, and safe classified over every pending draft the same way the review queue and bulk approve do (minus rows a worker is already draining), so every surface shows the same number.