Removes dependency on XformPrim class for create_prim

[Mayankm96]

Description

This MR removes the dependency on Isaac Sim XformPrim class for creating prims. The class mainly handled setting the world or local poses, as well as restting Xform operations. These are rather simple calls for which we don't need to go through Isaac Sim. The MR adds a new transform submodule that contains all the relevant functions as well as their tests.

Fixes # (issue)

Type of change

• New feature (non-breaking change which adds functionality)
• Breaking change (existing functionality will not work without user modification)

Checklist

• I have read and understood the contribution guidelines
• I have run the pre-commit checks with ./isaaclab.sh --format
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have updated the changelog and the corresponding version in the extension's config/extension.toml file
• I have added my name to the CONTRIBUTORS.md or my name already exists there

[greptile-apps]

Greptile Summary

This PR successfully removes the dependency on Isaac Sim's XFormPrim class from the create_prim function by implementing native USD transform operations.

Key Changes:

• Created new transforms.py module with functions: standardize_xform_ops, resolve_prim_pose, resolve_prim_scale, and convert_world_pose_to_local
• Refactored create_prim in prims.py to use native USD APIs instead of XFormPrim
• Added world-to-local coordinate conversion for the position parameter
• Moved transform utility functions from prims.py to the new transforms module
• Comprehensive test suite with 22 test cases covering edge cases, deprecation handling, and performance
• Documentation updated to include the new transforms module

Technical Details:

• The new implementation standardizes xform operations to USD convention: translate → orient (quaternion) → scale
• Handles deprecated operations (rotateXYZ, transform matrix) and unit scale resolution
• Maintains backward compatibility while removing the Isaac Sim dependency
• Performance benchmarking shows operations complete in <0.1ms per prim

Confidence Score: 5/5

• This PR is safe to merge with high confidence
• The implementation is well-architected with comprehensive test coverage (22 test cases), excellent documentation, proper error handling, and maintains backward compatibility. The refactoring removes an external dependency while preserving functionality through native USD APIs.
• No files require special attention

Important Files Changed

Filename	Overview
source/isaaclab/isaaclab/sim/utils/transforms.py	New module implementing USD transform operations: standardize_xform_ops, resolve_prim_pose, resolve_prim_scale, convert_world_pose_to_local - well-documented with comprehensive docstrings
source/isaaclab/isaaclab/sim/utils/prims.py	Removed XformPrim dependency from create_prim, added convert_world_pose_to_local call for world-to-local coordinate conversion, moved resolve_prim_pose and resolve_prim_scale to transforms module
source/isaaclab/test/sim/test_utils_transforms.py	Comprehensive test coverage for transforms module with 22 test cases covering standardize_xform_ops edge cases, world-to-local conversion, and performance benchmarks

Sequence Diagram

sequenceDiagram
    participant User
    participant create_prim
    participant convert_world_pose_to_local
    participant standardize_xform_ops
    participant USDGeom
    
    User->>create_prim: create_prim(prim_path, position, orientation, scale)
    
    alt position provided (world space)
        create_prim->>create_prim: Check parent prim exists
        create_prim->>convert_world_pose_to_local: Convert world pose to local
        convert_world_pose_to_local->>USDGeom: Get parent world transform
        convert_world_pose_to_local->>convert_world_pose_to_local: Compute local = world * inv(parent)
        convert_world_pose_to_local-->>create_prim: Return local translation & orientation
    else translation provided (local space)
        create_prim->>create_prim: Use translation directly
    end
    
    create_prim->>USDGeom: DefinePrim(prim_path, prim_type)
    USDGeom-->>create_prim: Return prim
    
    create_prim->>create_prim: Set attributes
    create_prim->>create_prim: Add semantic labels
    
    create_prim->>standardize_xform_ops: Standardize xform operations
    standardize_xform_ops->>USDGeom: GetLocalTransformation()
    standardize_xform_ops->>standardize_xform_ops: Remove deprecated ops (rotateXYZ, transform)
    standardize_xform_ops->>standardize_xform_ops: Resolve unitsResolve scale
    standardize_xform_ops->>USDGeom: Create/update translate op
    standardize_xform_ops->>USDGeom: Create/update orient op
    standardize_xform_ops->>USDGeom: Create/update scale op
    standardize_xform_ops->>USDGeom: SetXformOpOrder([translate, orient, scale])
    standardize_xform_ops-->>create_prim: Return success
    
    create_prim-->>User: Return created prim

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