Add changelog entry for Python library docs

fern/products/docs/pages/changelog/2026-03-02.mdx

@@ -0,0 +1,34 @@
+---
+tags: ["api-reference", "configuration"]
+---
+
+## Python library docs
+
+Add Python library reference documentation to your Fern docs site. Fern generates browsable, structured documentation directly from your Python SDK source code, including modules, classes, methods, and type signatures.
+
+To set up library docs, add a `libraries` configuration and a `library` navigation item to your `docs.yml`:
+
+```yaml title="docs.yml"
+libraries:
+  my-python-sdk:
+    input:
+      git: https://github.com/your-org/your-python-sdk
+    output:
+      path: ./generated/my-python-sdk
+    lang: python
+
+navigation:
+  - section: SDK Reference
+    contents:
+      - library: my-python-sdk
+```
+
+Then generate the reference pages:
+
+```bash
+fern docs md generate
+```
+
+This parses your Python source code on the server and generates MDX pages locally. The generated pages are resolved as first-class navigation sections in `fern docs dev` and `fern generate --docs`.
+
+Python is the first supported language, with more languages on the way.