How do you handle the shift from a quick Vibe Coded demo to a stable product?

We used AI to launch a quick test version in a few days and got early signups right away.

But once active users brought in edge cases and payments our quick prototype became really hard to maintain.

Instead of scrapping everything we decided to keep the frontend workflow but gradually rewrite backend services one module at a time.

It allowed us to keep the app live while building real stability.

If you built your early version with prompts what strategy worked best for turning it into prduction ready software?