fix: update index calculation for x-axis

[kofmania]

Context

Generating image slice(sagittal plane) data return wrong image in voxelManager.getSliceData

Changes & Results

Update index calculation code

file packages/core/src/utilities/VoxelManager.ts

current

this.setSliceDataValue(sliceData, i * depth + j, this._get(index));

new

this.setSliceDataValue(sliceData, i + j * height, this._get(index));

Testing

1. checkout test repo

• https://github.com/kofmania/cs3d-getslicedata-review

2. run

• npm i && npm run dev

3. open url

• http://localhost:5173

Checklist

PR

• My Pull Request title is descriptive, accurate and follows the
  semantic-release format and guidelines.

Code

• My code has been well-documented (function documentation, inline comments,
  etc.)

Public Documentation Updates

• [] The documentation page has been updated as necessary for any public API
  additions or removals.

Tested Environment

• "OS: Ubuntu 24.04
• "Node version: 22.16
• "Browser: Chrome Version 147.0.7727.101 (Official Build) (64-bit)

[Copilot]

Pull request overview

Fixes incorrect slice buffer indexing for sagittal (YZ) slice extraction in VoxelManager.getSliceData, which was causing wrong images when generating slice data.

Changes:

• Adjusted the linear index calculation used when writing into the sliceData buffer for slicePlane === 0 (YZ plane).

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[wayfarer3130]

Generally looks ok, can you create the requested unit test and document the return function?

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

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