Temporary files not cleaned up on Windows (tmpclaude-*-cwd, nul)

Bug Description

Claude Code leaves temporary files in the working directory on Windows that are not cleaned up after use.

Files affected

1. tmpclaude-XXXX-cwd - Multiple files containing the current working directory path
2. nul - File created when output is redirected to NUL (Windows null device) via bash

Environment

• Claude Code version: 2.1.6
• OS: Windows 10/11
• Shell: Git Bash / MinGW (used by Claude Code)

Steps to reproduce

1. Start Claude Code in any directory on Windows
2. Work with it for a while (run some commands)
3. Close/restart Claude Code
4. Check the working directory - temp files remain

Expected behavior

Temporary files should be automatically deleted when no longer needed.

Additional context

The nul file issue occurs because bash interprets > nul as a file path rather than the Windows NUL device. The redirect should use > /dev/null or > NUL: on Windows.