Per-campaign delivery funnel: delivered / read / failed, with the failure reason

The problem After a WhatsApp campaign runs, Chatwoot shows it as completed. It doesn't show how many messages were delivered, how many were read, how many failed — or why. Campaign carries campaign_status: active | completed | processing, and the per-message status exists on messages, but nothing aggregates it back to the campaign. Why it matters commercially "Completed" and "delivered" are different things, and the gap between them is where the money goes. A campaign to 240 contacts that reports completed might have delivered to 221 and failed on 8 — and those 8 failures each carry a Meta error code that tells the operator something actionable: this recipient hit their personal cap, this template is paused, this number isn't on WhatsApp. Without it, an operator sending campaigns from Chatwoot cannot answer "did it work?" without querying the database directly. What it would take An aggregate over messages grouped by campaign, surfaced on…