Improve document iteration from the main room chat

### User Problem

Iterating on created documents currently disrupts the workflow. I can only request changes when I am in the right-side document view, using the small input line there. This breaks the flow when I am working in the main room chat and want to continue refining the document naturally.

### Feature Request

Allow users to iterate on created documents directly from the main chat. When a document is active or referenced, exxperts should understand that requested changes apply to that document and update it without requiring the user to switch to the right-side document view.

**Example:**

- I create a document with exxperts.
- I continue working in the main chat.
- I say: “Make the introduction shorter and add a clearer example.”
- exxperts applies the change to the created document.
- I do not need to use the small input line in the right-side document view.

Start by tracing the main room chat flow and the existing right-side document iteration flow, then determine how active or referenced documents are identified. Done means a user can request document changes from the main chat and the active or referenced document is updated without switching views.

Written by the indexing model from the issue text.