Dispatcher.Send now returns []ChannelResult{Type, Err} alongside the
aggregated error, and scheduler.checkDomain increments
NotificationsTotal per channel type/status instead of a single
unconditional IncNotification("dispatch", newStatus) placeholder that
ignored per-channel delivery outcome.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BwxdSt4reTm7Dj1oxRvpP3
vasyansk
