release: bump version to 0.25.1

docs/CHANGELOG.md

@@ -7,6 +7,23 @@ This project follows the repository versioning rule:
 - `feature` -> `+0.1.0`
 - `bugfix` -> `+0.0.1`
 
+## 0.25.1
+
+Released: 2026-04-10
+
+### Highlights
+
+- Cleaned up the first persistent Playground rollout, fixed sidebar submenu persistence to match the intended operator behavior, and added reusable code-hygiene rules to prevent this class of drift from accumulating again.
+
+### Improved
+
+- Improved [backend/app/services/playground_chat_service.py](/home/ray/dev/linkong/planet/backend/app/services/playground_chat_service.py) and [frontend/src/pages/Playground/Playground.tsx](/home/ray/dev/linkong/planet/frontend/src/pages/Playground/Playground.tsx) by extracting repeated lookup, response, and request-action paths into shared helpers, reducing duplicated Playground flow code without changing behavior.
+- Improved [rules.md](/home/ray/dev/linkong/planet/rules.md) by adding a new `Code Hygiene - MANDATORY` section covering single-source-of-truth state, transitional cleanup, repeated-logic extraction, layout debugging order, and post-feature cleanup expectations.
+
+### Fixed
+
+- Fixed [frontend/src/components/AppLayout/AppLayout.tsx](/home/ray/dev/linkong/planet/frontend/src/components/AppLayout/AppLayout.tsx) so first-level menu expansion now behaves correctly across in-app navigation: `采集与数据` remains the default expanded group after refresh, while manually expanded groups stay open when navigating to their own child routes and reset only on page reload.
+
 ## 0.25.0
 
 Released: 2026-04-10