Discuss : Step-by-step recording 1.3

Discuss : Step-by-step recording 1.3
I would like a discussion around this 1.3 feature:

### Enhancement Summary
The feature should have a From-key-down -> To-key-Up Option.
The functionality would be that the recording would start emediately as a key is pressed, but end emediately when the key is released. That would result in dynamic length recording-steps.
My model also has a _record-toggle_ key, and a _step-back_-key, to be explained.

#### Justification
Current feature records in last-note steps. That would be the way you would work, if you make an absolutely quantized melody, but that is an unnatural rigid way to compose. Step-by-step, where you could _dynamically_ record what _is played_, would be more natural imo.
It could be called _free step-by-step_
The best way this could be implemented was that there was a _toggle-key_ for the record-feature, that would give the user an opportunity to _test the next_ note/ chord, before it was actually added to the melody.
If its difficult to understand what i mean, imagine this situation:
You are making a chord-progession like
I – vi – IV – V, then you are in doubt.
Here free step-by-step would be a good feature.
First new addition would be a _jump-back-key_ -could be back-space. Each press sends the play-head one note/ chord back, and then start replay, giving you a quick way to listen to 1,2,3 or more previous recorded chords, and _then_ you can _test_ a next chord.
You can repeat this sequence n times, until you have found the _best next_ chord, then you press the _step-by-step-toggle-key_ and play the found best chord in the free length you like, press the _step-by-step-toggle-key_ and search for the next best chord, in the same way.
I think that type of _step-by-step_ recording would be more natural functional, than the current rigid quantized, witch i find uninteresting to use.

No files, tests, or entry points are named. Start by locating the existing step-by-step recording and keyboard-handling implementation, then clarify the proposed toggle, key-down/key-up timing, replay, and step-back behavior. Done would mean an agreed design and an implemented free-length recording workflow matching those behaviors.

Written by the indexing model from the issue text.