feat: update StrokeControl and Slider components with consistent back…

[Shreyanshi210205]

…ground color and border styles

Description

This PR addresses multiple UI and usability issues in the StrokeControl component and its associated Slider (from shadcn/ui).

Previously:
1.The stroke width slider was not visible due to styling and visibility conflicts in Slider.jsx.
2.The stroke preview circle (representing brush width) was also invisible or misaligned.
3.When the circle became visible, it caused the toolbar border to shift as its size increased.
4.The layout lacked proper responsiveness on different screen sizes.

1.Fixed visibility issues
-Updated Slider.jsx styles in the shadcn/ui layer to ensure the slider track and thumb are properly visible.
-Ensured the stroke preview circle is always visible with consistent contrast against the background.
2.Fixed layout shifting
-Wrapped the preview circle in a fixed-height container and used absolute positioning to prevent the parent border from resizing.

Semver Changes

• Patch (bug fix, no new features)
• Minor (new features, no breaking changes)
• Major (breaking changes)

Issues

#21

Checklist

• I have read the Contributing Guidelines.

[Ayushivam22]

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[Shreyanshi210205]

@Ayushivam22 please provide labels .

[Ayushivam22]

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[Shreyanshi210205]

@Ayushivam22 Yes I am registered .