Shared State Setup

```bash
pip install ag-ui-adk
```

Shared state in ADK lives in `tool_context.state` — your tools write to
it directly and the runtime forwards updates to the UI. Wire your
`LlmAgent` with `AGUIToolset()` and CopilotKit takes care of the rest.

<DemoCode file="src/agents/hitl_in_chat_agent.py" region="setup" />

See `src/agents/shared_state_read_write_agent.py` for the bidirectional
pattern: a before-model callback reads UI-authored preferences out of
session state, and a `set_notes` tool writes agent-authored notes back.