docs: Add detailed audio pipeline investigation report

docs: add audit_production.md + plan_implementation_prod.md; fix admin phone field

chore: ignore and remove docs folder

feat(module1): integrate the 12-day curriculum in FR/WO with seed data and auto-routing

docs: add technical audit of the new pedagogical architecture

feat(whatsapp): implement interactive pedagogy architecture with Voice and Button routing

chore: setup whatsapp-worker for pure JS compilation and add Dockerfile fallback for Railway