* feat: incident severity matrix builder + guide Add an interactive severity matrix builder at /play/severity-matrix and a companion guide at /guides/incident-severity-matrix. The builder lets teams classify incidents by % users affected, security impact, and SLA breach — producing a deterministic severity level (SEV0–SEV3) with response time, escalation path, update cadence, and postmortem requirements. Includes test scenarios and customizable thresholds. The guide provides copy-ready status page message templates for all four severity levels and incident stages (Investigating → Identified → Monitoring → Resolved), postmortem requirements, severity vs priority, real-world classification examples, and tips. Also adds FAQPage JSON-LD structured data to curl, uptime-sla, and checker play tools that were missing it despite having faq frontmatter. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> * docs: add severity matrix builder planning spec Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> * chore: remove plan * chore: remove plan --------- Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>