Pretty nice proposal, well done!
It is probably overly optimistic about what can be achieved in three months - you've got
a lot of topics in there. Probably you could move several of them into a stretch goal section. I'd in particular encourage you to move module management in there and possibly GitHub interactions overall as well as those are likely to run into a series of prerequisites involving potentially substantial amounts of times from others that may have a hard time finding said time - I'm guilty of being in that category myself
While in theory I could see a seasoned developer with existing exposure to Terasology code
maybe making it through all that in one GSOC project better safe than sorry, you can always hit stretch goals if you are able to work fast.
Sometimes that could help substantially at this point is looking into more related code, such as the server facade. There's something keeping it and the game from running together at the moment, plus a few easy things to fix/improve/add. Seeing another related PR or two over the following week would be a very good extra