Chat Widget Improvements

[eyurtsev]

The chat widget doesn't quite feel like a chat experience yet, two improvements that could help:

1. Focus the mouse on the next required input when loading the playground?
2. Potentially swap roles of ctrl+enter <-> enter?

David's notes:

1. Clear out the input field when submitting a message
2. If a single chat widget is detected, consolidate input and output into a chat-like interface entirely.