GitHub Action for generating code review brief using ChatGPT AI (gpt-4, gpt-3.5-turbo model)

CodeLens: Production-grade FastAPI + React GPT Action delivering AI-powered code reviews via GitHub API integration, GPT-4o-mini structured analysis with token-aware chunking, Redis-backed caching, SSE streaming, PostgreSQL persistence, Prometheus observability, and a complete OpenAPI 3.1 schema for ChatGPT GPT Store deployment.