Google Apps Script Web-App Enhancement -- 2

I already have a live Google Apps Script web-app running at the URL above. I now need an experienced Apps Script developer to step in, review the current codebase, and extend or fix its functionality while keeping the existing deployment intact. Key points • All work must be done exclusively in Google Apps Script—no external runtimes. • You will receive access to the current project so you can audit the code, identify pain points, and propose clear improvements. • Final deliverable is an updated, fully tested version of the script re-deployed to the same web-app URL, along with a concise changelog and any setup notes needed for future maintenance. If you’ve built or debugged complex Apps Script web-apps before, I’d love to hear how you would approach tightening the code and adding the requested refinements.