doc: Render mermaid

Author: effigies

docs/conf.py

@@ -14,6 +14,7 @@
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration
 
 extensions = [
+    'sphinxcontrib.mermaid',
     'myst_parser',
     'sphinx_copybutton',
     'sphinxext.rediraffe',

docs/dataset-lifecycle.md

@@ -14,7 +14,7 @@ pass through, and the mutations that drive transitions between them.
 A dataset's state is determined by two fields: whether it has any
 snapshots and whether it is public.
 
-```mermaid
+```{mermaid}
 stateDiagram-v2
     [*] --> Draft
     Draft --> Embargoed : createSnapshot()
@@ -126,7 +126,7 @@ delete.
 Snapshots can be independently deprecated without changing the dataset's
 state.
 
-```mermaid
+```{mermaid}
 stateDiagram-v2
     [*] --> Active : createSnapshot()
     Active --> Deprecated : deprecateSnapshot()

docs/index.md

@@ -90,6 +90,7 @@ structure of our package and hosting setup may be interested in the following se
 :maxdepth: 1
 
 architecture
+dataset-lifecycle
 maintenance
 Source repository (GitHub) <https://github.com/OpenNeuroOrg/openneuro>
 ```

docs/specs/2026-04-06-doi-lifecycle-design.md

@@ -72,7 +72,7 @@ DataCite defines three DOI states:
 
 ### State diagram
 
-```mermaid
+```{mermaid}
 stateDiagram-v2
     [*] --> Draft : createSnapshot()
     Draft --> Draft : deprecateSnapshot() / undoDeprecateSnapshot()