Fix: update box and height to use responsive sizes properly

[krishan711]

Description

Screenshots:

Checklist:

• I have updated the CHANGELOG with a summary of my changes
• I have updated the documentation accordingly

[Copilot]

Pull request overview

This PR updates layout sizing so that Box and Stack correctly honor responsive height and width base values, and updates the changelog to reflect recent responsive sizing fixes.

Changes:

• Update Box to derive its base width/height from widthResponsive.base / heightResponsive.base when explicit width/height props are not provided.
• Update Stack to derive its base width/height from widthResponsive.base / heightResponsive.base similarly, ensuring CSS variables and full-size flags stay in sync.
• Adjust the unreleased changelog entries describing responsive sizing corrections across EqualGrid, Box, and Stack.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/particles/box/component.tsx	Computes height and width using nullish coalescing with heightResponsive.base / widthResponsive.base, so the base responsive size is respected by the Box layout and CSS variables.
src/layouts/stack/component.tsx	Aligns Stack’s base height/width with heightResponsive.base / widthResponsive.base, keeping the base CSS variables consistent with responsive sizing behavior.
CHANGELOG.md	Updates unreleased notes to describe responsive sizing fixes, though one entry currently uses a prop name that doesn’t match the actual EqualGrid API.

[Copilot]

This changelog entry refers to sizeResponsive.base in EqualGrid, but the component API uses childSizeResponsive.base (see src/layouts/equalGrid/component.tsx:19-25). To avoid confusion for consumers, consider updating the wording to match the actual prop names and to only mention heightResponsive.base / widthResponsive.base for components that actually expose those props (Box and Stack, not EqualGrid).

Suggested change

	- [MINOR] Correction for using `sizeResponsive.base` size in `EqualGrid`
	- [MINOR] Correction for using `heightResponsive.base`, `widthResponsive.base` size in `EqualGrid`, `Box` and `Stack`
	- [MINOR] Correction for using `childSizeResponsive.base` size in `EqualGrid`
	- [MINOR] Correction for using `heightResponsive.base`, `widthResponsive.base` size in `Box` and `Stack`