feat: add FableLoom autopilot self-improvement

[atomantic]

Summary

• add an opt-in, content-free post-mortem for paused or failed FableLoom editorial autopilot runs
• queue deduplicated, approval-gated PortOS CoS tasks for confident workflow defects
• surface task links and preserve terminal facts across late cancellation

Test plan

• cd server && npm test -- --run services/fableLoom/editorialSelfImprove.test.js services/fableLoom/editorialAutopilot.test.js routes/fableLoom.test.js ../scripts/migrations/322-fableloom-editorial-self-improve-stage.test.js ../scripts/generate-prompt-stage-call-sites.test.js
• cd client && npm test -- --run src/components/fableloom/LoomEditorialAutomation.test.jsx src/services/apiFableLoom.test.js
• cd client && npm run lint
• cd client && npm run build