[FEATURE] Resizable (or shorter) chat input box in the Claude Desktop Code tab

### 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 the Claude Desktop app, Code tab, the chat input box grows with the text typed into it. When a session has finished a long turn and I reply step by step to its report, my own reply gets long and the input box expands to roughly two thirds of the window height. The session's report is then squeezed into the top third of the screen: I read a paragraph, scroll the small pane, type, scroll again. There is no way to trade height between the two panes.

### Proposed Solution

A draggable splitter between the transcript pane and the input box, so the input box height can be pulled up or down by hand (and remembered per session or globally). If a splitter is too much, a simpler fix would do: cap the input box at about one third of the window height and let it scroll internally beyond that.

### Alternative Solutions

Currently I draft long replies in a separate editor and paste them in one go, or I keep the reply short and split it over several messages, which loses the structure of a point-by-point answer.

### Priority

High - Significant impact on productivity

### Additional Context

Windows desktop app, Code tab, interactive sessions with long structured reports.

Start by locating the Claude Desktop Code tab implementation and the transcript/input pane layout; no repository files or tests are named in the issue. Done means the input can be resized with a splitter or capped at roughly one third of the window with internal scrolling, while the transcript remains usable.

Written by the indexing model from the issue text.