In-Chat annotation

**What problem would this solve?**
Highlighting a portion of a text to discuss about it is difficult. This affects the ease of discussing a section of the chat.

**What would a good outcome look like?**
When a user highlights a portion of the chat, the user should be granted that ability to add the portion to chat and discuss about it.

- [x] I have verified this does not duplicate an existing feature request.

Look at the chat UI components in the frontend codebase, likely in a directory like 'src/ui' or 'src/frontend'. Identify how text selection is currently handled and where chat messages are rendered. The feature requires adding a UI interaction for highlighting text and a mechanism to reference that selection in a new chat message. Check existing state management for chat interactions to understand how to integrate the annotation.

Written by the indexing model from the issue text.