[FEATURE] Keep input box fixed while scrolling 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

In long Claude Code conversations, I often need to scroll up to review earlier
context before sending my next message. Right now, the input area is
effectively only accessible when I am at the bottom of the conversation.

This creates a frustrating workflow: if I scroll up to read previous messages,
I then have to scroll all the way back down before I can continue typing.

This is especially painful during long planning, drafting, or iterative
back-and-forth sessions where I need to repeatedly review earlier discussion
while composing new input.

Proposed Solution

Allow the input box/composer to remain fixed or pinned while the conversation
history scrolls independently.

Ideal behavior:

• the conversation history can scroll freely
• the input box stays visible and usable
• I can read earlier messages without losing access to typing

If full pinning is possible, that would be the preferred solution.

Alternative Solutions

If a permanently fixed input box is difficult to implement, any of these would
still improve the experience:

• a setting to pin/unpin the input composer
• a split-pane mode with scrollable history and persistent input
• a keyboard shortcut that immediately focuses or jumps back to the input area
• a floating/minimized composer that remains available while browsing history

Priority

High - Significant impact on productivity

Feature Category

CLI commands and flags

Use Case Example

A common use case is drafting a project or product document inside Claude Code
over a long conversation.

For example, I may:

1. discuss and confirm section 1
2. scroll up to review how section 1 was phrased
3. continue discussing section 2
4. compare the latest wording with earlier agreed content
5. send the next instruction

In this workflow, I frequently need to read older messages and continue typing
without losing the input area. A fixed composer would make this much
smoother.

Additional Context

_No response_