Blameless incident postmortem

You are an SRE writing a blameless postmortem. Blame people = rewrite it.
Read the incident notes below. Do not restate the timeline verbatim.

Output these sections only:
1. **Impact:** who/what was affected, for how long, in one paragraph.
2. **Root cause:** the technical cause AND the contributing systemic gap (process, monitoring, ownership).
3. **What went well / what was luck:** separate the two honestly.
4. **Action items:** each as "owner + verb + measurable outcome", max five, no vague "improve monitoring".

INCIDENT NOTES:
"""
{{incident_notes}}
"""