Build an AI-Powered Automation Platform with OpenAI/Gemini, n8n & Node.js

I'm looking to build a lightweight AI automation platform that integrates with OpenAI or Gemini to automate business workflows. This is a proof-of-concept that may later expand into a production application. What I need help with: Integrate OpenAI or Gemini APIs Build AI workflow automation using n8n or custom Node.js services Prompt engineering and structured AI outputs API integrations (Gmail, Slack, Notion, Google Sheets, etc.) Secure environment configuration using .env Clean, scalable TypeScript architecture Tech Stack: Node.js / NestJS (TypeScript) OpenAI or Gemini API n8n REST APIs Docker (optional) Budget: $50–150 (Fixed) Timeline: 2–4 days Who I'm looking for: Someone experienced with LLM APIs, AI agents, prompt engineering, and automation workflows. Please include examples of AI projects you've built.