We need to deliver a multi-role platform based on Fly.io (state-machine driven + Stripe payments/escrow + ad bidding + 3D digital humans via pixel streaming).Using low-code + modular composition, we are building an international platform. It must be explicitly stated that this is not an MVP. [Deployment & Infrastructure] 1) The platform must run on Fly.io (frontend/backend, jobs/queues, WebSocket/WebRTC services as needed). 2) Proper logging/monitoring/alerting is required, including alerts for third-party integration failures and cost/usage anomalies. [Core Requirements (Important)] 1) Multi-role / four portals: end users, service providers, maintenance staff, and admin portal (different permissions and flows). 2) Critical business flows must be implemented using a state machine / state-driven architecture (no “skipping steps”): order → payment → escrow/split → fulfillment → acceptance → settlement → refund/dispute, with full traceability, rollback rules, and audit logs. 3) Payments: Stripe (payments, payouts, webhooks). Must handle idempotency, webhook replay protection, and concurrency-safe state transitions. 4) Automation / orchestration: n8n (or similar) as the workflow hub, connecting Supabase, payments, notifications, ads, and digital humans. 5) Conversational guidance: use Botpress (or similar tools) for conversations + next-step actions. 6) Advertising: creative management + delivery configuration + analytics; ad slot bidding/auction (e.g., Prebid.js / RTB model). Bidding logs must be retained and auditable. 7) Multilingual: UI/content must support multiple languages and integrate language detection and translation APIs. [3D Digital Humans (one component, but mandatory)] 1) MetaHuman + Unreal Engine for creating 3D digital humans. 2) Pixel Streaming (WebRTC) to stream UE video to web/mobile clients. 3) A unified control interface to switch avatars/actions and drive lip-sync via TTS audio, integrated with state-machine-driven guidance flows. Please reply with: 1) Similar projects you have delivered (if possible, provide links/demos). 2) Recommended Fly.io architecture and service decomposition. 3) Estimated timeline and price range for each phase. 4) What materials you need from me to proceed (execution step flows, required module list, etc.). 5)phased timeline, rough price range.