fix: add Windows UTF-8 encoding environment variables for terminals

[roomote]

Related GitHub Issue

Closes: #10709

Description

This PR attempts to address Issue #10709 where terminal output exhibits character corruption on Windows systems using non-UTF-8 encodings like GBK (code page 936).

Implementation Details:

• Added Windows-specific UTF-8 environment variables to both VSCode terminals (Terminal.ts) and Execa terminals (ExecaTerminalProcess.ts)
• The following environment variables are now set on Windows:
  • PYTHONIOENCODING=utf-8: Forces Python to use UTF-8 for stdin/stdout/stderr
  • PYTHONUTF8=1: Enables Python 3.7+ UTF-8 mode
  • RUBYOPT=-EUTF-8: Forces Ruby to use UTF-8 encoding

These variables encourage UTF-8 encoding for common programming language runtimes, reducing character corruption when the Windows system code page is non-UTF-8.

Test Procedure

1. Unit Tests: Added new test file Terminal.getEnv.spec.ts and updated ExecaTerminalProcess.spec.ts with tests for Windows UTF-8 environment variables
2. Manual Testing: On a Windows system with GBK encoding (code page 936), verify that terminal output from Python and Ruby scripts displays correctly without character corruption

To run the tests:

cd src && npx vitest run integrations/terminal/__tests__/ExecaTerminalProcess.spec.ts integrations/terminal/__tests__/Terminal.getEnv.spec.ts

Pre-Submission Checklist

• Issue Linked: This PR is linked to an approved GitHub Issue (see "Related GitHub Issue" above).
• Scope: My changes are focused on the linked issue (one major feature/fix per PR).
• Self-Review: I have performed a thorough self-review of my code.
• Testing: New and/or updated tests have been added to cover my changes (if applicable).
• Documentation Impact: I have considered if my changes require documentation updates (see "Documentation Updates" section below).
• Contribution Guidelines: I have read and agree to the Contributor Guidelines.

Documentation Updates

• No documentation updates are required.

Additional Notes

Feedback and guidance are welcome! This fix addresses encoding issues for Python and Ruby scripts. For cmd.exe/PowerShell commands that output Windows-native text (not through Python/Ruby), users may still need to manually run chcp 65001 as a workaround until a more comprehensive solution is implemented.

---

Important

Adds Windows-specific UTF-8 environment variables to prevent character corruption in terminals, with tests to ensure correct behavior.

• Behavior:
  • Sets Windows-specific UTF-8 environment variables in ExecaTerminalProcess.ts and Terminal.ts to prevent character corruption.
  • Environment variables set: PYTHONIOENCODING=utf-8, PYTHONUTF8=1, RUBYOPT=-EUTF-8.
• Testing:
  • Adds ExecaTerminalProcess.spec.ts to test UTF-8 environment variable settings and preservation/override of existing variables.
  • Adds Terminal.getEnv.spec.ts to test environment variable settings for Windows and non-Windows platforms.
• Misc:
  • Closes issue [BUG] In the inline terminal, the output of any command exhibits character corruption. #10709 related to character corruption on Windows terminals.

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[roomote]

Rooviewer   See task on Roo Cloud

Reviewed the Windows UTF-8 encoding fix. Found one consistency issue to address.

• Inconsistent platform handling: ExecaTerminalProcess.ts sets Python/Ruby UTF-8 vars unconditionally while Terminal.ts only sets them on Windows

_{Mention @roomote in a comment to request specific changes to this pull request or fix all unresolved issues.}

[roomote]

The comment says "Windows-specific" but these environment variables are set unconditionally on all platforms. In contrast, Terminal.ts correctly guards these with process.platform === "win32". This creates inconsistent behavior: Execa terminals will set these vars on macOS/Linux while VSCode terminals will not. Consider either adding a platform check here to match Terminal.ts, or updating the comment to explain why these are intentionally set on all platforms (e.g., for consistency with the existing LANG/LC_ALL unconditional override).

_{Fix it with Roo Code or mention @roomote and request a fix.}