Adds Examples with sphinx gallery.

* docs: add sphinx-gallery for runnable example scripts

Introduces sphinx-gallery as an alternative to Jupyter notebooks for
lightweight, fast-running code examples. Adds a minimal example script
(weighted voting game with Shapley values) and gitignores the generated
auto_examples/ output directory.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* ci: fail docs build on warnings

Adds -W --keep-going to sphinx-build so the doc_build job treats any
Sphinx warning as an error. --keep-going ensures all warnings are
reported before the build exits.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: mmschlk

.github/workflows/ci.yml

@@ -145,9 +145,8 @@ jobs:
                     sudo apt-get install -y pandoc
             -   name: Install dependencies
                 run: uv sync --no-dev --group docs
-                # TODO(mmshlk) Turn this step to fail on warnings in the future.
             -   name: Build documentation
-                run: uv run --no-sync sphinx-build -b html docs/source docs/build/html
+                run: uv run --no-sync sphinx-build -W --keep-going -b html docs/source docs/build/html
     # ----------------------------------------------------------------------------------------------
     # Code Coverage
     # ----------------------------------------------------------------------------------------------

.gitignore

@@ -182,3 +182,5 @@ game_storage/*
 
 # install artifacts
 src/shapiq/_version.py
+docs/source/auto_examples/
+docs/source/sg_execution_times.rst