[Feature Request] Improve PowerShell shell configuration support for Windows

(Written and provided verbatim by Claude Code.)

## Shell configuration for Windows (PowerShell support)

Version: 2.0.75

Platform: Windows 11

### Problem

The Bash tool on Windows runs through a bash wrapper that mangles PowerShell syntax:

• $_ becomes empty (bash interprets it as a variable)
• $false/$true get stripped or mangled
• Complex pipelines with ForEach-Object fail
• Quote escaping becomes extremely fragile

Example:

```powershell
# Intended command
Get-ScheduledTask | Where-Object { $_.TaskName -match 'sync' }

# What bash wrapper produces
Get-ScheduledTask | Where-Object { extglob.TaskName -match 'sync' }

  Current Workarounds

  - Wrapping in cmd /c "powershell.exe -NoProfile -Command '...'"
  - Using -Confirm:0 instead of -Confirm:$false
  - Avoiding complex pipelines entirely

  These are inconsistent and error-prone.

  Requested Feature

  A setting to configure the shell used by the Bash tool:

  {
    "shell": "powershell"
  }

  Or a separate PowerShell tool that bypasses bash interpretation entirely.

  Impact

  Significantly improves Windows developer experience where PowerShell is the native shell.