Web: Step markers don't align with thumb positions

[bananer]

Environment

• are you using the new architecture? yes

• which version of react & react-native are you using?

    "react": "19.1.0",
    "react-native": "0.81.4",

Description

On Web, stepNumber and StepMarker don't align with the thumb position towards the left and right edge. For the center value it matches, but the further you go left and right the further off it is.

When comparing Web and Android, the underlying problem might also be that on web, the whole slider has less margin left and right.

On web, the slider hast the same width as the Button below:

Same code on Android, the slider has less width and the step markers align:

Reproducible Demo

https://snack.expo.dev/@bananer_rw/react-native-slider-step-marker-repro

[mikolajwilczek]

I've created a PR to fix the step marker alignment on web.

I noticed the web slider is wider than on native (due to different margin handling), but I focused on fixing the alignment issue. I think the width difference could be addressed separately if needed.
Please test and let me know if this resolves the issue.