[BUG] Edit tool corrupts Windows-1252 encoding to UTF-8

Environment

• Platform (select one):
• [X] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: 1.0.72
• Operating System: Ubuntu 24.04.2 LTS
• Terminal: VSCode Terminal

Bug Description

The Edit tool automatically converts Windows-1252 encoded files to UTF-8, corrupting accented characters in the process.

Steps to Reproduce

1. Open any Windows-1252 encoded file with Portuguese accented characters
2. Use Edit tool to make any modification
3. File gets automatically converted to UTF-8, corrupting all accented characters throughout the file

Expected Behavior

Edit tool should detect and preserve the original file encoding instead of forcing UTF-8 conversion.

Actual Behavior

The Edit tool automatically converts Windows-1252 encoded files to UTF-8, corrupting accented characters in the process.