update changelog

Author: github-actions[bot]

docs/changelog/changelog.mdx

@@ -4,6 +4,13 @@ icon: "clock"
 iconType: "solid"
 ---
 
+<Update label="v0.39.0" description="February 26, 2025">
+### [Lazy Graph Compute Mode and new agent run snapshots.](https://github.com/codegen-sh/codegen-sdk/releases/tag/v0.39.0)
+- Implement Lazy Graph Compute Mode
+- Add agent run snapshots feature
+- Update API reference documentation
+</Update>
+
 <Update label="v0.38.0" description="February 26, 2025">
 ### [Adds ripgrep search tool and updates API docs.](https://github.com/codegen-sh/codegen-sdk/releases/tag/v0.38.0)
 - Integrate ripgrep in search tool