ENH: wire the JupyterLite build into the docs (JupyterLite split 5/5)

.circleci/config.yml

@@ -232,6 +232,17 @@ jobs:
           no_output_timeout: 10m
           command: |
             ./tools/circleci_download.sh
+      # Ensure the data the JupyterLite notebooks need is on disk so conf.py can
+      # copy the required subset for the build. lite_data fetches only the
+      # curated files the browser notebooks use (from the MNE-lite-data OSF
+      # project) instead of the full sample/kiloword/erp_core/mtrf/eegbci
+      # datasets, which slims the build. The curated files share hashes with the
+      # full datasets, so on a full build that already downloaded them nothing
+      # extra is fetched.
+      - run:
+          name: Ensure MNE data for JupyterLite
+          command: |
+            python -c "import mne; mne.datasets.lite_data.data_path(update_path=True)"
       - run:
           name: Verify build type
           command: |

.gitignore

@@ -104,5 +104,11 @@ venv/
 .hypothesis/
 .ruff_cache/
 .ipynb_checkpoints/
+
+# generated by the JupyterLite docs build (doc/conf.py)
+doc/jupyterlite_contents/*
+!doc/jupyterlite_contents/.gitkeep
+doc/lite_extra/
+
 /.claude/
 uv.lock

doc/Makefile

@@ -68,7 +68,7 @@ html_dev-noplot: html-noplot
 html_dev-front: html-front
 
 linkcheck:
-	@$(SPHINXBUILD) -b linkcheck -D nitpicky=0 -q -D plot_gallery=0 -D exclude_patterns="cited.rst,whats_new.rst,configure_git.rst,_includes,changes/dev" -d _build/doctrees . _build/linkcheck
+	@$(SPHINXBUILD) -b linkcheck -D nitpicky=0 -q -D plot_gallery=0 -D exclude_patterns="cited.rst,whats_new.rst,configure_git.rst,_includes,changes/dev,jupyterlite_contents,lite_extra,pypi" -d _build/doctrees . _build/linkcheck
 
 doctest:
 	$(SPHINXBUILD) -b doctest $(ALLSPHINXOPTS) _build/doctest

doc/changes/dev/14157.newfeature.rst

@@ -0,0 +1 @@
+Add an "Open in JupyterLite" badge to the tutorials and examples that can run in the browser, by `Natneal B`_.