Markdown support

[MrOrz]

• Use React-markdown to display chat messages
• Ensure that tool calls and messages are rendered in the same order as in ADK session events.

---

🛠 Implementation Guidance for Jules (Post-PR #18 Architecture)

To ensure high-quality implementation following the server functions architecture from PR #18, please follow these technical requirements:

1. Type Refactoring (src/lib/adk.ts)

• Inheritance: Redefine ChatMessage to extend AdkContent (from adk-types.d.ts).
• Field Alignment: Use parts: Array<AdkPart> as the primary source of truth for message content.
• Cleanup: Remove the separate text: string and toolCalls: Array<ToolCall> fields. Retain UI-specific metadata like id, isStreaming, timestamp, and author.

2. Logic Update (src/lib/chatCache.ts)

• Direct Mapping: Refactor applyEventToState to stop manually extracting text and toolCalls strings.
• Order Preservation: Directly map event.content.parts to the ChatMessage.parts array.
• Streaming Handling: When event.partial is true, append the incoming text chunk to the last text part in the parts array if it exists; otherwise, push a new text part. This ensures that text and tool calls are interleaved exactly as received from the ADK stream via the runChat server function.

3. Frontend Rendering (AgentMessage.tsx & UserMessage.tsx)

• Markdown Library: Install and use react-markdown and remark-gfm.
• Part-based Rendering: Iterate through message.parts and render based on type:
  • text: Render using ReactMarkdown.
  • functionCall: Render using existing tool call UI components.
• Security: react-markdown + remark-gfm provides safe DOM construction by default.
• Styling: Ensure Markdown content (headers, lists, links) is properly styled using Tailwind CSS (consider adding @tailwindcss/typography if needed).

[google-labs-jules]

Jules is on it. When finished, you will see another comment and be able to review a PR.

[google-labs-jules]

Ready for a review! A PR has been created.

[google-labs-jules]

I apologize, but I encountered an unexpected error and wasn't able to complete the task.