I am working on a TUI tool for Git/jj to handle staging/splitting. Could you tell me more about what workflow would be problematic for you? For example, if you had to select lines that go in the first commit/staging area, does that work? Would it be better or worse if, for each line, you had to decide whether it would go into the first commit/staged vs second commit/unstaged area? Do you ever need to invert the first commit/staging area vs second commit/unstaged area?