New

• sending-ips: admin /admin/sending-ips dashboard + docs update #522
• sending-ips: worker reads active set from DB + auto-retire stale rows #521
• sending-ips: add SPF auto-sync via Cloudflare DNS API #520
• sending-ips: persist PTR + DNSBL state, auto-pause on bad signals #519
• sending-ips: add Hetzner Robot API reconciler with Redis lease #518
• sending-ips: add lifecycle registry and node-local discovery #517