DOC: Add accelerated pixi-build workflow to build documentation

Document the libitk-wrapping conda package workflow for building
remote module wheels without recompiling ITK from source. Includes
instructions for building and installing the package, environment
variable overrides for custom ITK branches, and cross-references
between the ITK and module build docs.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hjmjohnson

docs/Build_ITK_Module_Python_packages.rst

@@ -198,6 +198,52 @@ For more control over build option, call ``build_wheels.py`` directly with
      --no-build-itk-tarball-cache
 
 
+.. _accelerated-builds:
+
+Accelerated Builds with libitk-wrapping (pixi-build)
+=====================================================
+
+When ITK is pre-installed in the conda/pixi environment via the
+``libitk-wrapping`` package, the build system automatically skips the
+expensive ITK C++ compilation (steps 01 and 02). This reduces remote
+module build times from ~1-2 hours to ~15 minutes.
+
+To use this workflow, first build and install the ``libitk-wrapping``
+package:
+
+.. code-block:: bash
+
+   cd packages/libitk-wrapping
+   pixi build
+
+Then build your module wheel — ITK will be detected automatically:
+
+.. code-block:: bash
+
+   pixi run -e linux-py311 python scripts/build_wheels.py \
+     --platform-env linux-py311 \
+     --module-source-dir /path/to/ITKMyModule \
+     --skip-itk-build \
+     --skip-itk-wheel-build \
+     --no-build-itk-tarball-cache
+
+The detection checks ``CONDA_PREFIX`` and ``PIXI_ENVIRONMENT_DIR`` for
+``lib/cmake/ITK-*/ITKConfig.cmake``. When found, the console will print::
+
+   Detected conda-installed ITK at <path> (via $CONDA_PREFIX)
+   Using conda-installed ITK; skipping superbuild and C++ build steps.
+
+To override the ITK source repository and tag for the ``libitk-wrapping``
+build (e.g., to test a feature branch):
+
+.. code-block:: bash
+
+   export ITK_GIT_URL="https://github.com/MyOrg/ITK.git"
+   export ITK_GIT_TAG="my-feature-branch"
+   cd packages/libitk-wrapping
+   pixi build
+
+
 Module Dependencies
 ===================
 

docs/Build_ITK_Python_packages.rst

@@ -132,6 +132,13 @@ Finished wheels are placed in ``<build-dir-root>/dist/``.
    ``--build-itk-tarball-cache`` to save the result as a reusable tarball
    and avoid rebuilding on subsequent runs.
 
+.. tip::
+   For even faster builds, install the ``libitk-wrapping`` conda package
+   (see ``packages/libitk-wrapping/``). When present in the pixi/conda
+   environment, the build system automatically detects it and skips the
+   ITK C++ compilation entirely. See
+   :ref:`Build ITK Module Python Packages <accelerated-builds>` for details.
+
 
 Key Options
 ===========