[Feature]: Add pending UI for bubble component

[fu050409]

BubbleList should display a pending bubble when new input provided and a new AI agent request created.

[Raven-Book]

can you assign the issue to me?

[fu050409]

@Raven-Book Of course :D

[Raven-Book]

Resolved: #20

[fu050409]

Resolved: #20

@Raven-Book lol.

This comment should be left at the description field of a PR, not as a issue comment.