Turn a postmortem into an on-call SKILL.md runbook

Convert this incident postmortem into an on-call runbook as SKILL.md. The postmortem is narrative; the skill must be runnable at 3am without reading the whole doc.

Postmortem paste:
[timeline, impact, root cause, what mitigated, what failed, follow-up tickets]

Systems and tools named in the incident:
[monitoring, dashboards, CLI, kubectl contexts, feature flags — names only]

Deliver SKILL.md with:
1. Purpose — one sentence: respond to recurrence of [incident class] using verified steps.
2. When to use / when not to use (symptoms that match vs similar false alarms).
3. Severity and escalation: who to page, in role terms (on-call primary, service owner) — pull names from postmortem if present, else [define in team roster].
4. Detection: signals to look for (metrics, logs, alerts) with dashboard links or query snippets copied from the postmortem only.
5. Mitigation steps — numbered, each ending with Verify: and a concrete check (metric threshold, command exit 0, user-visible recovery).
6. Communication template: three bullets for status update (impact, action, next update time) — no marketing language.
7. Rollback or kill-switch steps if the postmortem mentions them; otherwise write "not documented — add before relying on this skill."
8. Pitfalls from the postmortem: five mistakes that slowed response, rewritten as do-not-do bullets.
9. Done means: incident mitigated, escalation completed if needed, follow-up ticket ids listed, postmortem link stored in skill header comment.

Rules:
- Do not invent runbook steps not supported by the postmortem; mark gaps as [add verification].
- Do not paste secrets, tokens, or customer data from the postmortem — redact to placeholders.
- Markdown only, no preamble outside SKILL.md.