Prevent code from stomping on user slider dragging

[myieye]

Currently if the user starts dragging the slider component, code can interrupt them, which is bad UX.
I think that by default or at least optionally, code should be blocked from doing so.

I ran into this problem while binding the slider to audio playback. There's no clean way to pause the audio fast enough when the user starts dragging, in order to preserve the user's selected position when they e.g. just click somewhere on the slider

To make it work, I very messily exposed drag start and stop events and had to make sure I wrote to the slider value in an $effect (rather than passing in the actual audio time $state), so that I could avoid touching the value when the user started sliding.