Now that the code is hosted at https://transcriber.toolforge.org we need to get it to a point where it can be loaded as a user script on Wikisources with something like the following in common.js:
mw.loader.load( 'https://transcriber.toolforge.org/gadget.js' );
This will involve changing some of the system of packaging so that the wrapper code (as seen for example in https://ban.wikisource.org/wiki/Sang_Angangg%C3%A9:SGill_(WMF)/common.js ) is not needed in common.js but instead is part of the tool's code.
The idea is to set up a script end point that will mean it's not necessary for users to update their common.js when there's a change to the code. This will mean we can roll out updates more easily, and everyone will get the latest code.
(Long-term, this is perhaps not the best way to do it, but it replicates the status quo and will serve as a reasonable next step in development.