[BUG] VSCode Terminal: /ide integration stopped working after v2.1.56 (regression from v2.1.52 fix)

Bug Description

When running Claude Code from VSCode's integrated terminal (PowerShell), the /ide integration no longer works. Claude Code does not detect that it is running inside VSCode, so IDE features (file editing, diff view, etc.) are unavailable.

This was previously fixed in v2.1.52, but the issue has regressed after v2.1.56.

Steps to Reproduce

1. Open VSCode (latest version) on Windows 11
2. Open the integrated terminal (PowerShell)
3. Run claude in the terminal
4. Attempt to use /ide integration features
5. Claude Code does not detect VSCode — IDE integration is not available

Expected Behavior

Claude Code should detect that it is running inside VSCode's integrated terminal and enable IDE integration features, as it did in v2.1.52.

Actual Behavior

Claude Code does not detect VSCode terminal environment. /ide integration is unavailable.

Version Information

• Claude Code version: 2.1.58
• OS: Windows 11 (10.0.26200)
• VSCode: Latest version
• Terminal: VSCode integrated terminal (PowerShell)
• Shell: PowerShell

Version History

| Version | /ide Integration |
|---------|-----------------|
| v2.1.52 | ✅ Working (fix was applied) |
| v2.1.56+ | ❌ Broken again (regression) |
| v2.1.58 | ❌ Still broken |

Possibly Related

• v2.1.55: "Fixed BashTool failing on Windows with EINVAL error"
• v2.1.56: "VS Code: Fixed another cause of openLast crashes"
• v2.1.53: Multiple Windows-specific crash fixes

The regression may be related to changes in how the extension detects or communicates with the CLI process running in the integrated terminal.