[Feature Request] Add mode to disable Enter key message submission

Bug Description
Hi 🫶
A new claude mode where enter do not send the message.
When I want to write a longer message with full context, I always have to remember to press Option+Enter (or the equivalent) to create a new line instead of sending the message.
It would be great to have a mode where you can write a longer block of text without worrying about accidentally sending it.

Environment Info

• Platform: darwin
• Terminal: pycharm
• Version: 2.1.44
• Feedback ID: 6ae9c9ba-341d-480f-ac4d-5be70542ee04