Can't drag and drop text

### Your use case

#### What would you like to do?

I would like to drag and drop texts from a different app to the messages form field.

#### Why would you like to do it?

I usually select, drag and drop text between apps because it's easier than copy and paste when you're copying a lot of excerpts.

#### How would you like to achieve it?

### Have you considered any alternatives?

_No response_

### Additional context

_No response_

The issue names no files, tests, or entry points. Start by locating the message composer and its drag-and-drop handling, then reproduce dragging selected text from another application; done means the text appears in the messages field without breaking existing input behavior.

Written by the indexing model from the issue text.