I’m generally for more of this kind of thing, but be aware that annotating all the places where actions happen is kind of a pain, we’ve already have one person get started on it and then give up. As placeybordeaux notes, the current state of the code makes an achievements system more difficult to implement than t could be.
That’s generally not how github works, feel free to fork the project, make improvements, and request that they be merged. Ideally you can coordinate here, in the github issue tracker, and in our IRC channel, which will minimise the risk of you working on something that doesn’t get merged.
If you mean “Is anyone working on this currently?”, no one is.
I’m not sure what you mean by “organized push”. We are continuously working on cleaning up and rearchitecting the code base, it’s a process, not a single task. If you’d like to propose specific cleanups or undertake them yourself, please feel free.