feat(minor): options to control citation detail, agent response rendering.
- `Agent.render_agent_response` method to display agent response, controled by option `hide_agent_response`
- `AgentConfig.hide_agent_response` - set to `True` to hide agent response (useful where tool-handlers send large response to LLM, but
we don't want to clutter display with it)
- `ChatAgentConfig.full_citations` - whether to show citations with content or not. If `False`, only show main reference in footnote, not the
whole content.