Configurable framerate and diff-rendering

          @leostera This is awesome sauce! I think the situation has improved for me but not entirely.

I still see an issue from #34 but it happens not so frequently to me. Previously, I had to restart my app 7 times to avoid hanging. Now I need to restart it 7 times to observe hanging, which is an improvement!

At this point, I started thinking that my view function may generate lots of garbage, and the GC struggles to process everything at 60 FPS (default).

I wonder if Mint Tea can add something like has_diff : 'model -> 'model -> bool to t

https://github.com/leostera/minttea/blob/3e386136d315c60c16ea39b94789fbb7761003f5/minttea/app.ml#L1-L5

So that it can avoid calling view entirely if the model didn't change unlike the current implementation where we compare already rendered buffer:

https://github.com/leostera/minttea/blob/3e386136d315c60c16ea39b94789fbb7761003f5/minttea/renderer.ml#L26

Alternatively, exposing the fps setting from start may help app developers reduce their resource usage (I don't really need 60 fps)

https://github.com/leostera/minttea/blob/3e386136d315c60c16ea39b94789fbb7761003f5/minttea/minttea.ml#L9-L26

Originally posted by @chshersh in https://github.com/leostera/minttea/issues/38#issuecomment-2021312464

Start with minttea/app.ml and minttea/renderer.ml at the linked locations to understand the current model and rendered-buffer comparisons, then inspect minttea/minttea.ml where start is defined. Clarify whether the intended result is model-based diffing, configurable FPS, or both; done means the selected behavior is exposed and prevents the reported rendering overhead.