Feat: Implement Neo.ai.Chat (Reference UI)

Create a reference implementation of a Modern AI Chat Interface to demonstrate the capabilities of the new markdown.VDom component.

Features:

1. Streaming: Connect to a mock stream to demonstrate smooth text appending.
2. Typing Effect: Implement a "Typing Buffer" that linearizes bursty network packets into a smooth visual flow (e.g., 1 char/10ms).
3. Auto-Scroll: Robust "stick-to-bottom" logic that respects user scroll intent.
4. Architecture: Use the markdown.VDom component to ensure 60fps rendering even during heavy streams.