Update dependency groups

README.md

@@ -56,6 +56,21 @@ linear systems, ideally with double precision.
 
 Install from PyPI with pip:
 ```bash
+pip3 install meanas
+```
+
+Optional extras:
+
+- `meanas[test]`: pytest and coverage
+- `meanas[docs]`: MkDocs-based documentation toolchain
+- `meanas[examples]`: optional runtime dependencies used by the tracked examples
+- `meanas[dev]`: the union of `test`, `docs`, and `examples`, plus local lint/docs-publish helpers
+
+Examples:
+```bash
+pip3 install 'meanas[test]'
+pip3 install 'meanas[docs]'
+pip3 install 'meanas[examples]'
 pip3 install 'meanas[dev]'
 ```