Add rotation examples for transform

[Maximus-08]

Summary

This PR expands the transform documentation with rotation examples and adds test coverage for those workflows.

Changes

• add CoordinateTransformations.LinearMap examples for rotating polygons
• document rotation around both the origin and a polygon centroid
• add transform tests covering:
  • rotation around the origin
  • rotation around the centroid while preserving centroid and area
• add a tutorial example in creating_geometry.md showing both rotation approaches visually

Fixes: #192

All tests passed locally

[Copilot]

Pull request overview

Adds documentation and tests demonstrating that GO.transform accepts callable CoordinateTransformations.jl transforms (notably LinearMap-based rotations), including examples for rotating about the origin and about a polygon’s centroid.

Changes:

• Added new transformation tests covering polygon rotation around the origin and around the centroid (centroid/area invariants).
• Expanded transform docstring with CoordinateTransformations.jl LinearMap rotation examples.
• Extended the “creating geometry” tutorial with rotation examples and visualization.

Reviewed changes

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

File	Description
test/transformations/transform.jl	Adds rotation-focused testsets for GO.transform, including centroid/area assertions.
src/transformations/transform.jl	Updates transform documentation to explicitly mention callable transforms and shows LinearMap usage.
docs/src/tutorials/creating_geometry.md	Adds tutorial content demonstrating rotation about origin vs centroid using composed transforms.

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[Maximus-08]

Hey @asinghvi17 Please take a look when you're free, the failed check does not seem related to changes

[asinghvi17]

Thanks for the PR! I think LinearMap is a bit too complex to be in a beginner tutorial. Would you mind changing this to use something from Rotations.jl instead?

[Maximus-08]

Sure I will take a look at Rotations.jl and confirm the approach with you

[Maximus-08]

Hey would RotMatrix be a good option, we could use Angle2d but it can only be applied to 2D .

[asinghvi17]

I would recommend Angle2D. 99% of users here will be performing 2D operations, so that's what is relevant to them.