binance/binance-api-postman ? reverse-engineered prompt

Build me a clean Postman collection pack for the Binance public API, with separate collections and environments for the main areas like spot, margin, futures, and other market data endpoints.

I want it to be easy to import into Postman and use right away after I add my own API key and secret. Please include clear environment variables, the signing setup for private requests, and example requests that work out of the box for common endpoints. Make sure the collections are organized in a way that feels simple for someone who just wants to test Binance APIs without digging through docs.

Also include a short README that explains how to import the files, choose the right environment, add credentials, and troubleshoot common issues like missing API keys or bad signatures. If you need current endpoint details or Postman best practices, look them up online first so the collection matches what Binance uses now.