About adding it in the UI, yes, I agree, but it will be in some 'advanced' part of the upload page. We plan to remake it soon, but we are still unsure how, it will mostly depend on our testing of the new uploading back-end / encoder.
In the end, I want it to stay as simple as possible for your grandma to be able to upload, but I want to give access to these 'expert' features as well, it's just not a big priority atm compared to the rest.
Well imo I think you should reduce the bundling you seem to be doing to the javascript files it makes inputing the hashes/magnet links harder because the devtools window sometimes stops responding. Also it makes the code harder to read and possibly patch myself if i want to test something.