feat(core): add ai model switch ui (#12266)

Close [AI-86](https://linear.app/affine-design/issue/AI-86)

![截屏2025-05-14 11.32.41.png](https://graphite-user-uploaded-assets-prod.s3.amazonaws.com/sJGviKxfE3Ap685cl5bj/b92d5c32-fa5a-4afd-93e6-3699347575be.png)

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

## Summary by CodeRabbit

- **New Features**
  - Introduced AI model switching in chat, allowing users to select from multiple AI models during conversations.
  - Added a floating menu for easy AI model selection within the chat interface.
  - Enabled visibility of the AI model switcher through a new experimental feature flag, configurable in workspace settings (canary builds only).

- **Enhancements**
  - Improved session management in the chat panel for smoother model switching and state handling.
  - Updated localization to support the new AI model switch feature in settings.

- **Bug Fixes**
  - None.

- **Chores**
  - Registered new components and services to support AI model switching functionality.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/core/src/desktop/pages/workspace/detail-page/tabs/chat.tsx

@@ -47,6 +47,7 @@ export const EditorChatPanel = forwardRef(function EditorChatPanel(
     searchMenuConfig,
     networkSearchConfig,
     reasoningConfig,
+    modelSwitchConfig,
   } = useAIChatConfig();
 
   useEffect(() => {
@@ -73,6 +74,7 @@ export const EditorChatPanel = forwardRef(function EditorChatPanel(
       chatPanelRef.current.searchMenuConfig = searchMenuConfig;
       chatPanelRef.current.networkSearchConfig = networkSearchConfig;
       chatPanelRef.current.reasoningConfig = reasoningConfig;
+      chatPanelRef.current.modelSwitchConfig = modelSwitchConfig;
       chatPanelRef.current.extensions = editor.host.std
         .get(ViewExtensionManagerIdentifier)
         .get('preview-page');
@@ -107,6 +109,7 @@ export const EditorChatPanel = forwardRef(function EditorChatPanel(
     networkSearchConfig,
     searchMenuConfig,
     reasoningConfig,
+    modelSwitchConfig,
   ]);
 
   return <div className={styles.root} ref={containerRef} />;