Document isaaclab.utils.warp.fabric kernels

The submodule was not surfaced anywhere in the Sphinx tree, so :func:
cross-references to its kernels (added in the changelog fragment for
this branch and used by FabricFrameView throughout) did not resolve.

Add a Warp Fabric kernels subsection to isaaclab.utils.rst that
automodule's the submodule, and add __all__ to fabric.py so the
generated page lists only the eight public kernels - the type aliases
(FabricArrayMat44d, ArrayUInt32, ...) and the re-imported `wp` /
`TYPE_CHECKING` / `Any` symbols stay out of the rendered docs.

The page covers both the pre-existing kernels
(compose/decompose_fabric_transformation_matrix_*_warp_arrays,
set_view_to_fabric_array, arange_k) and the four kernels added on
this branch.

Author: pv-nvidia

docs/source/api/lab/isaaclab.utils.rst

@@ -188,3 +188,16 @@ Warp operations
    :members:
    :imported-members:
    :show-inheritance:
+
+Warp Fabric kernels
+^^^^^^^^^^^^^^^^^^^
+
+Warp kernels for reading and writing Fabric ``Matrix4d`` attributes
+(``omni:fabric:worldMatrix`` / ``omni:fabric:localMatrix``) via
+:class:`wp.fabricarray` and :class:`wp.indexedfabricarray`.  Used by
+:class:`~isaaclab_physx.sim.views.FabricFrameView` to keep child world and
+local matrices consistent without round-tripping through USD.
+
+.. automodule:: isaaclab.utils.warp.fabric
+   :members:
+   :show-inheritance:

source/isaaclab/isaaclab/utils/warp/fabric.py

@@ -15,6 +15,17 @@
 
 import warp as wp
 
+__all__ = [
+    "arange_k",
+    "compose_fabric_transformation_matrix_from_warp_arrays",
+    "compose_indexed_fabric_transforms",
+    "decompose_fabric_transformation_matrix_to_warp_arrays",
+    "decompose_indexed_fabric_transforms",
+    "set_view_to_fabric_array",
+    "update_indexed_local_matrix_from_world",
+    "update_indexed_world_matrix_from_local",
+]
+
 if TYPE_CHECKING:
     FabricArrayUInt32 = Any
     FabricArrayMat44d = Any