Fix improved brush shape for rotated images

[Devu-trenser]

Context

Fixes incorrect shape rendering when using brush tools with circular/spherical/rectangle shapes in rotated viewports.

Fixes : #2651

⚠️⚠️ This PR targets the arul-trenser:feat-axis-based-image-stretching branch from #2443.

Changes & Results

Changes

• Fixed incorrect shape rendering in rotated/oblique viewports.
• Updated fill logic to use viewport-aligned axes.
• Improved voxel inclusion checks for better geometric consistency.
• Fixed rectangle point ordering instability.
• Reduced slice leakage and unintended fills across neighboring slices.

Results
Before

• Circular/spherical/rectangluar brushes could appear as distorted shapes in rotated views.
• Rectangle rendering was unstable depending on viewport orientation.

After

• Circular and spherical brushes maintain almost similar to the expected geometry in rotated/oblique views.
• Improved consistency and stability across all supported brush shapes.

Testing

1. Run the Axis-based Image Stretching example.
2. Rotate the viewport to different oblique angles (e.g. 40°–45°).
3. Draw annotations using:
   • Circular Brush
   • Sphere Brush
   • Rectangle Brush
4. Verify:
   • Shapes render correctly in rotated views.
   • Rectangle fills remain stable and properly aligned.

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: 20
• [] "Browser: Chrome 139

[claude]

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