I’m quite interested in this as well, for the same reason.
Unfortunately, I don’t believe there’s currently any way to accomplish this.
Even developing a custom Pack I believe is out of the question because Coda Packs don’t support tracking keyboard events.
I believe the best (somewhat clunky) short term solution is to set up an automation to press the button whenever the row changes.
When a user presses enter, they will “save” the text in the text box. This will then trigger the action. But this also means that if the user changes the text then clicks outside the textbox, it will also trigger the automation, so this isn’t an ideal solution.