We'll definitely add a PRQL/SQL block to the UI soon (you will be able to toggle to select which one you'd like).
On that point - PRQL doesn't natively support PIVOT statements. As a hack, we made our own flavor of PRQL with a PIVOT statement and we parse that to SQL CTEs to make it work for now. I will be submitting a pull request to PRQL to add support to get around this.
We're working on saving queries to local storage as well as sharing via downloadable config files (we're thinking a PRQL file with some sugar that when uploaded, recreates the entire transform)