Migrate a React/Express.js SaaS Web App off Replit to a Production Stack

Overview: I am the founder of a B2B fire safety inspection web platform currently hosted on Replit. We are outgrowing Replit due to AI costs and the need for robust background job scheduling (automated compliance emails and inspection reminders). I need an experienced developer to migrate our full-stack application to a scalable, cost-effective infrastructure. Current Tech Stack: •Frontend: React 18, TypeScript, Tailwind, Vite, IndexedDB (for offline mode) •Backend: Express.js, TypeScript •Database: PostgreSQL via Drizzle ORM (multi-tenant architecture) •AI: Google Gemini Vision (OCR) and OpenAI (Summaries) The Target Migration Stack: •Backend & Frontend Hosting: Railway •Database: Supabase (migrating existing PostgreSQL schema and data) •Job Queuing: Trigger.dev (to replace our current server/report-scheduler.ts and server/reminder-scheduler.ts for reliable email delivery and AI processing) •AI Integration: Move off Replit's AI integrations; connect directly to OpenAI and Google Gemini APIs using our own keys to reduce costs. Requirements: •You must have proven experience migrating Node.js/PostgreSQL apps to Railway and Supabase. •You must know how to set up cron jobs/scheduled tasks using a modern queue like Trigger.dev. •No full rewrites. We are lifting and shifting the existing logic and optimizing the infrastructure. Please reply with a brief summary of a similar migration you have done and your estimated timeline for a phased rollout.