Runs the full postmortem workflow: gathers incident context, writes a blameless report to a gitignored `postmortem/` folder, and creates action items. Use whenever the user wants to review or document any production incident or outage. Triggers on: '/postmortem', 'write a postmortem', 'incident review', 'post-incident', 'blameless review', 'what broke and why', 'SEV1/SEV2 report', or 'help me write up what happened'.
