[BUG] Spinner animation printing on multiple lines instead of updating in place (Windows)

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?

The loading spinner animation is no longer updating in place. Instead, each animation frame is printed on a new line, creating multiple lines of output:

✢ Simmering… (esc to interrupt · 1m 2s · ↓ 2.7k tokens · thought for 46s)
· Simmering… (esc to interrupt · 1m 2s · ↓ 2.7k tokens · thought for 46s)
✢ Simmering… (esc to interrupt · 1m 2s · ↓ 2.7k tokens · thought for 46s)

• Simmering… (esc to interrupt · 1m 2s · ↓ 2.7k tokens · thought for 46s)

✶ Simmering… (esc to interrupt · 1m 2s · ↓ 2.7k tokens · thought for 46s)
✻ Simmering… (esc to interrupt · 1m 2s · ↓ 2.7k tokens · thought for 46s)
✽ Simmering… (esc to interrupt · 1m 2s · ↓ 2.7k tokens · thought for 46s)
✽ Simmering… (esc to interrupt · 1m 3s · ↓ 2.7k tokens · thought for 46s)

This appears to be a carriage return (CR) vs line feed (LF) issue where the terminal is not properly handling the CR character to update the same line.

What Should Happen?

The spinner animation should update in place on the same line, with each frame replacing the previous one, creating a smooth animated effect. This was the previous behavior.

Error Messages/Logs

No error messages - just visual rendering issue with the spinner animation.

Steps to Reproduce

1. Start Claude Code on Windows
2. Execute any command that shows the loading spinner (e.g., asking a question that requires thinking time)
3. Observe the spinner output

Expected: Spinner animates in place on one line Actual: Each spinner frame prints on a new line
Cannot read CLI output

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.73

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

termainal : Powershell 7.5.4

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