Route hub-originated alerts (silence-detector/pmidle/dormant-PM) OFF HUMAN_AGENT to a PM/ops lane

Elazar noise-reduction / elazar-contact cutover follow-up. Hub-originated notices (sender='llmmsg-srv-hub') currently land on HUMAN_AGENT (Elazar's contact inbox): [silence-detector] agent-quiet alerts, pmidle/dormant-PM alerts, busy-nudges, command receipts. Post-cutover the escalation backstop (MSG-264) blanket-mutes sender='llmmsg-srv-hub' (exact-match) from email escalation - correct, because these are non-must-reach operational notices. BUT audit correctly flagged a genuinely urgent hub-originated alert then has no email path at all. Real fix = ROUTING: emit silence/pmidle/dormant-PM alerts to a PM/ops lane (or aro), off HUMAN_AGENT entirely, so the contact inbox holds only real inbound. Closes audit's concern without weakening the hub mute. Non-blocking on the MSG-264 bounce (0fc97b4/v2.33.4). Ref mem:hub-noise-reduction-initiative. PM ruled 2026-07-12 to keep the full hub mute; this WI is the durable resolution of the load-bearing gap coder-llmmsgsrv-cc flagged.