docs(dart): fix example references in documentation

Remove references to non-existent Flutter example app and update to
accurately describe the CLI example that is actually provided.

The SDK supports Flutter but the current example is a CLI tool demonstrating
the protocol functionality.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: mattsp1290

docs/sdk/dart/overview.mdx

@@ -126,15 +126,17 @@ The Dart SDK supports all Dart platforms:
 - **Dart VM**: Server-side and CLI applications
 - **Dart Web**: Browser-based applications
 
-## Example Applications
+## Example Application
 
-Explore complete examples in the [examples directory](https://github.com/ag-ui/ag-ui/tree/main/sdks/community/dart/example):
+Explore the CLI example in the [example directory](https://github.com/ag-ui/ag-ui/tree/main/sdks/community/dart/example):
 
-- **Simple Chat**: Basic agent conversation
-- **Tool Usage**: Demonstrates tool calling
-- **State Management**: Shows state updates and persistence
-- **Flutter Integration**: Complete Flutter app with UI components
-- **Error Handling**: Demonstrates retry and error recovery
+- **CLI Tool**: Interactive command-line tool demonstrating:
+  - Basic agent conversation
+  - Tool-based generative UI flow
+  - Server-Sent Events streaming
+  - Auto-tool mode for non-interactive execution
+  - JSON output for debugging
+  - Error handling and retry logic
 
 ## Testing