feat: add support for VSCode file encodings

[roomote]

Related GitHub Issue

Closes: #11002

Description

This PR attempts to address Issue #11002 by adding support for VSCode file encodings.

Problem: Roo Code previously hardcoded UTF-8 encoding for all file read/write operations. When editing files with non-UTF-8 encodings (like CP 852), the content was read as UTF-8, modified, and written back as UTF-8, which corrupted special characters (e.g., č, ć, ž, š, đ).

Solution: This PR implements encoding detection and preservation:

1. New encoding utility (src/utils/fileEncoding.ts):

   • Gets the file encoding from VSCode settings (files.encoding)
   • Provides readFileWithEncoding() and writeFileWithEncoding() functions
   • Converts content to UTF-8 internally for AI processing
   • Converts back to original encoding when saving
   • Includes fallback to UTF-8 if encoding conversion fails (with console warning)

2. Modified DiffViewProvider.ts:

   • Uses encoding-aware reading when opening files
   • Uses encoding-aware writing when saving files directly

3. Modified ApplyPatchTool.ts:

   • Uses encoding-aware reading for patch operations
   • Uses encoding-aware writing for file moves

4. Added iconv-lite dependency:

   • Popular, well-tested library for encoding conversion in Node.js
   • Supports a wide range of encodings including CP 852

Test Procedure

1. Unit tests: Run cd src && npx vitest run utils/__tests__/fileEncoding.spec.ts - all 17 tests pass
2. Manual testing:
   • Configure VSCode with "files.encoding": "cp852" for a workspace
   • Open a file with CP 852 characters (č, ć, ž, š, đ)
   • Make edits using Roo Code
   • Verify the file is saved with CP 852 encoding and characters are preserved

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.

Screenshots / Videos

N/A - No UI changes, this is a backend encoding fix.

Documentation Updates

• No documentation updates are required.
• Yes, documentation updates may be useful to explain that Roo Code now respects VSCode's files.encoding setting.

Additional Notes

This implementation follows the user's requested approach from the issue discussion:

1. Relies on VSCode file encodings (not automatic detection)
2. Includes fallback to UTF-8 with console warning if encoding conversion fails
3. No special file patterns or workspace settings needed

Feedback and guidance are welcome!

---

Important

Adds support for VSCode file encodings, enabling encoding-aware file operations and fallback to UTF-8 if conversion fails.

• Behavior:
  • Adds readFileWithEncoding() and writeFileWithEncoding() in fileEncoding.ts to handle file encodings based on VSCode settings.
  • Falls back to UTF-8 with a warning if encoding conversion fails.
• Integration:
  • Updates DiffViewProvider.ts to use encoding-aware reading and writing for file operations.
  • Updates ApplyPatchTool.ts to use encoding-aware reading and writing for patch operations.
• Dependencies:
  • Adds iconv-lite to package.json for encoding conversion support.
• Testing:
  • Adds unit tests in fileEncoding.spec.ts to verify encoding handling and fallback behavior.

^{This description was created by for 57f07a8. You can customize this summary. It will automatically update as commits are pushed.}

[roomote]

Rooviewer   See task on Roo Cloud

Review completed. No issues found.

The implementation correctly adds encoding support for VSCode's files.encoding setting. The new fileEncoding.ts utility properly reads/writes files with the configured encoding and includes robust fallback handling. The integration with DiffViewProvider.ts and ApplyPatchTool.ts is correct. Tests are comprehensive.

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