[FEATURE] Keep input prompt pinned/visible while scrolling through conversation history

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

When Claude provides a long response, I often need to scroll up to review the output while composing my next message. Currently, scrolling up hides the input prompt, and scrolling back down to type means losing sight of the content I was just reading. This constant back-and-forth between reading Claude's response and typing a follow-up is disruptive, especially during complex coding sessions where I need to reference specific parts of the response.

Proposed Solution

Keep the input prompt pinned to the bottom of the terminal at all times, even while scrolling through conversation history. The conversation output above would scroll independently while the prompt remains fixed and ready for input. This is similar to how chat applications (Slack, Discord, etc.) handle their UI — the message history scrolls while the compose area stays in place.

This could work as:

• A split-pane approach within the TUI where the scrollable conversation area and the input area are independent regions
• A toggleable mode (e.g., via a keybinding) that locks the prompt to the bottom

Alternative Solutions

_No response_

Priority

High - Significant impact on productivity

Feature Category

Interactive mode (TUI)

Use Case Example

_No response_

Additional Context

Related: #16784 (keyboard shortcut to jump between user prompts) — these features would complement each other well.