Configure OpenAI Codex to Work Directly With My Existing Firebase Project

I have an existing Flutter/Firebase application and I'm trying to use OpenAI Codex as part of my development workflow. I need someone to configure Codex so it can directly work with my existing Firebase project folder instead of me copying and pasting code manually. This is not a Flutter development job. This is purely a tooling/setup task. I need someone who has actual experience using and setting up OpenAI Codex with existing codebases. What I need: Configure Codex to work with my existing Firebase Functions folder Verify it has the appropriate permissions to edit files Verify it can create, modify, and save files successfully Explain the setup so I understand how to use it going forward Answer a few workflow questions while we test it Requirements: Experience with OpenAI Codex Experience with Git Experience with Firebase Functions (Node.js) Good English communication Deliverable: By the end of the session, Codex should be able to directly edit my Firebase project, and I should understand how to use it effectively.