What problem does this address?

In the native mobile editor, it's not possible to paste content into the editor title field and have it split correctly between the title and body.

Web	Native Mobile

What is your proposed solution?

Just like on the web, content pasted into the title field should split correctly between the title and body. It might be reasonable to put whatever follows the first new-line character in the body, keeping what's before it in the title. That said, there might be a web implementation we can use to avoid re-implementing this.