Add AI playground and frontend layout guidelines

docs/CHANGELOG.md

@@ -7,6 +7,35 @@ This project follows the repository versioning rule:
 - `feature` -> `+0.1.0`
 - `bugfix` -> `+0.0.1`
 
+## 0.24.0
+
+Released: 2026-04-09
+
+### Highlights
+
+- Added a dedicated `AI Playground` admin entry so operators can validate provider connectivity and run controlled situational-analysis prompts from the main frontend without introducing a separate UI service.
+- Established a first explicit frontend layout rulebook centered on single-screen workspaces, internal module scrolling, and BGP-style page composition for future admin pages.
+
+### Added
+
+- Added [frontend/src/pages/Playground/Playground.tsx](/home/ray/dev/linkong/planet/frontend/src/pages/Playground/Playground.tsx), introducing the first dedicated AI testing workspace with provider status visibility, prompt/result tabs, and collapsible operator guidance.
+- Added [docs/frontend-layout-guidelines.md](/home/ray/dev/linkong/planet/docs/frontend-layout-guidelines.md), documenting the repository standard for one-screen admin workspaces and module-local overflow handling.
+- Added [docs/ai-playground-development-plan.md](/home/ray/dev/linkong/planet/docs/ai-playground-development-plan.md), capturing the completed AI gateway/UI work and the next delivery phases for BGP briefs, evidence-first inputs, and future agent runtime expansion.
+
+### Improved
+
+- Improved [frontend/src/components/AppLayout/AppLayout.tsx](/home/ray/dev/linkong/planet/frontend/src/components/AppLayout/AppLayout.tsx) and [frontend/src/App.tsx](/home/ray/dev/linkong/planet/frontend/src/App.tsx) by wiring `AI Playground` into the main admin navigation and route tree instead of pointing operators to a nonexistent `aiprovider` chat page.
+- Improved [planet.sh](/home/ray/dev/linkong/planet/planet.sh) by replacing the incorrect `localhost:8010/chat` closeout link with the frontend `AI Playground` entry.
+- Improved [docker-compose.yml](/home/ray/dev/linkong/planet/docker-compose.yml) by attaching `./aiprovider/.env` to the `aiprovider` service so provider identity, model, and credentials actually reach the running container.
+- Improved [README.md](/home/ray/dev/linkong/planet/README.md) by linking the new frontend layout guidance and AI Playground development plan.
+- Improved [frontend/src/index.css](/home/ray/dev/linkong/planet/frontend/src/index.css) by refining the Playground workspace into a notebook-friendly left-sidebar plus right-tabbed layout, reusing thin scrollbars, and making provider/help/result regions degrade more gracefully under constrained height.
+
+### Fixed
+
+- Fixed the local AI status flow so provider configuration no longer appeared permanently `disabled / not configured` merely because `aiprovider/.env` was not mounted into the container.
+- Fixed repeated `Provider 状态` refetching when switching away from and back to `/playground` by caching the last known provider status within the browser session until the operator explicitly refreshes it.
+- Fixed several Playground layout regressions where auxiliary panels could push the result area out of view or clip provider details without exposing internal scrolling.
+
 ## 0.23.4
 
 Released: 2026-04-08