How would you provide a user with ability to change code in browser without downloading anything on local machine, and commit that code to GIT?
Clarification: original question contained additional points, now moved to separate question.
I answer to the first question only.
How would you provide a user with ability to change code in browser without downloading anything on local machine, and commit that code to GIT?
Gitab offers a full featured Web IDE like in the following snapshot:
Edit
Here is the screenshot about the console activation button.