[BUG] Claude Code Filesystem Provider Fails in MINGW64 Environment

Environment

• Platform (select one):
• [x] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: 1.0.51
• Operating System: Windows 10/11 with MINGW64 (Git Bash)
• Terminal: Powershell

Bug Description

Claude Code's Edit/Write tools fail in MINGW64/Git Bash environments due to path conversion and URL encoding issues in the filesystem provider.

Steps to Reproduce

1. Open Claude Code in MINGW64/Git Bash environment
2. Navigate to any directory
3. Create a test file: echo "test" > test-file.txt
4. Attempt to use Edit tool on the file
5. Observe filesystem provider error

Expected Behavior

Edit/Write tools should work correctly in MINGW64 environments with proper path handling.

Actual Behavior

High severity for Windows developers using Git Bash - all Edit/Write operations fail.

Additional Context

Root Cause Analysis

1. MINGW64 shell reports working directory as /c/Users/Greg/website (Unix-style)
2. Node.js process sees working directory as C:\Users\Greg\website (Windows-style)
3. Edit/Write tools convert relative paths to Windows absolute paths
4. Paths get URL-encoded: c%3A%5CUsers%5CGreg%5Cwebsite%5Cfilename.txt
5. _claude_fs_right: protocol cannot resolve the malformed URI

Suggested Fix

• Detect MINGW64 environment and handle path conversion appropriately
• Ensure filesystem provider can handle both Unix-style and Windows-style paths
• Prevent URL encoding issues with Windows drive letters in filesystem URIs