fix(core): artifact rendering issue in standalone ai chat panel (#13166)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Improved chat component to support document link navigation directly
from chat messages, allowing users to open documents in the workbench
when links are clicked.

* **Refactor**
* Streamlined notification handling and property access in document
composition tools for a cleaner user experience.
* Updated import statements for improved code clarity and
maintainability.
  * Enhanced code artifact tool rendering to ensure consistent theming.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/core/src/desktop/pages/workspace/chat/index.tsx

@@ -58,7 +58,9 @@ function useCopilotClient() {
 
 function createMockStd(workspace: Workspace) {
   workspace.meta.initialize();
-  const store = workspace.createDoc().getStore();
+  // just pick a random doc for now
+  const store = workspace.docs.values().next().value?.getStore();
+  if (!store) return null;
   const std = new BlockStdScope({
     store,
     extensions: [...getViewManager().config.init().value.get('page')],
@@ -187,7 +189,7 @@ export const Component = () => {
     content.session = currentSession;
     content.workspaceId = workspaceId;
     content.extensions = specs;
-    content.std = mockStd;
+    content.host = mockStd?.host;
     content.docDisplayConfig = docDisplayConfig;
     content.searchMenuConfig = searchMenuConfig;
     content.networkSearchConfig = networkSearchConfig;