[Feature Request] Static/pinned input field while scrolling through long output

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

Problem

When receiving long output (e.g., code review feedback, diffs, or explanations), the input field scrolls out of view. To respond, I have to scroll to the bottom of the terminal, type my answer, and then scroll back up to reference the content.

This creates a frustrating workflow when I need to read and reference long text while formulating my response.

Proposed Solution

Implement a split-pane terminal UI with:

• A scrollable output area at the top for Claude's responses
• A fixed/pinned input field at the bottom that remains visible while scrolling

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

CLI commands and flags

Use Case Example

• Reading through lengthy code review feedback while composing a response
• Referencing long explanations or diffs while asking follow-up questions
• Any scenario where the output exceeds the terminal height

Additional Context

Gemini CLI implements this with their "inner shell" feature - the input prompt stays pinned at the bottom while the output area above is independently scrollable. Users can press Ctrl+F to focus the shell.

<img width="1973" height="490" alt="Image" src="https://github.com/user-attachments/assets/93b08212-2967-449d-9226-a6265ec47119" />