[BUG] Broken text alignment and fragmented output rendering in CLI

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Describe the bug
When using the Claude Code CLI, the response output suffers from severe formatting issues. Sentences appear fragmented, with random line breaks and erratic indentation. Specifically, parts of the sentences are cut off or start in the middle of the terminal line (e.g., "...dan destekleniyorum"), and subsequent paragraphs are heavily indented without cause.

To Reproduce
Steps to reproduce the behavior:

1. Start a session in the CLI (Windows Terminal / PowerShell).
2. Enter a simple query (e.g., "sen kimsin" / "who are you").
3. Observe the streaming response.

Expected behavior
The response should be strictly left-aligned and formatted as a coherent text block, similar to standard CLI outputs.

Screenshots
<img width="1520" height="586" alt="Image" src="https://github.com/user-attachments/assets/d4ab1661-651e-463f-94ac-3bdc0a2dd0d7" />

Environment (please complete the following information):

• OS: Windows (deduced from file path syntax)
• Shell: [PowerShell / CMD / Bash?]
• Claude Code Version: [Varsa versiyon numarasını buraya yaz]

Additional context
It seems like the render engine struggles with terminal width calculation or stream buffering, causing the first few characters of lines to disappear or shift incorrectly. The output "onorepo'sunda..." suggests a cut-off of the word "monorepo".

What Should Happen?

<img width="1536" height="450" alt="Image" src="https://github.com/user-attachments/assets/706ac58b-11f0-4681-b917-e8a7d79fac8e" />

Error Messages/Logs

no error

Steps to Reproduce

.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

v2.0.73

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_