[FEATURE] Allow mulitple message in /btw mode

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

I would like to have a quick chat about some topic using the /btw command and then continue with the untouched session

Proposed Solution

Allow /btw mode to exchange multiple messages before it is exited

Alternative Solutions

Fork into a new session

Priority

Low - Nice to have

Feature Category

Interactive mode (TUI)

Use Case Example

_No response_

Additional Context

_No response_