feat: add Supabase auth + 5 new pipeline stages

feat: PDF and DOCX stage/full-build reports for HITL and autonomous flow

fix: strict_gates defaults to false, remove dead code

feat: rewarding build UX + Docker fixes + web docs cleanup

feat: Supabase auth + Razorpay billing + fix API double-URL bug

fix: frontend distinguishes backend-offline vs LLM-key-missing errors

feat: connect frontend to HuggingFace Space backend

feat: add skip coverage option to Design Studio and Human In Loop Build pages

feat: add HITL webapp with 3 UX improvements