Internal Terminal on Windows defaults to cmd.exe instead of PowerShell, with no shell selection #15095

Describe the bug

The Terminal in Kilo Desktop (Windows) opens cmd.exe instead of the OS default PowerShell, and there is no setting to choose the shell. Any command using PowerShell syntax fails: running New-Item -ItemType Directory "$env:LOCALAPPDATA\Temp\test" in the internal Terminal errors out, while the identical command succeeds in the user's normal PowerShell window.

Evidence (Kilo Desktop 0.1.11, Windows 11): the engine's shell resolution falls back to process.env.ComSpec || "cmd.exe" when no shell is specified, so cmd.exe is the effective default. The Terminal feature docs and General settings document no shell selection.

To Reproduce

1. On Windows 11, open any workspace in Kilo Desktop and open the Terminal panel.
2. Observe the prompt is a cmd.exe prompt, not PowerShell (no PS prefix, no $env: expansion).
3. Run a PowerShell cmdlet, e.g. New-Item -ItemType Directory "$env:LOCALAPPDATA\Temp\x" - it fails with a command-not-recognized error.
4. The same command works in a standalone PowerShell window on the same machine.

Expected behavior

Follow platform convention (VS Code's terminal.integrated.defaultProfile defaults to PowerShell on Windows; Windows Terminal and JetBrains both honor a per-user default):

• Default the internal Terminal to PowerShell (prefer pwsh.exe when installed, else powershell.exe) on Windows.
• Expose the shell choice in Settings -> Terminal (PowerShell 7 / Windows PowerShell 5.1 / cmd / Git bash), per workspace where sensible.

Please validate that:

• I have searched the existing issues and this isn't a duplicate.

Environment: Kilo Desktop 0.1.11, Windows 11, signed in.

Prepared with Kilo (AI assistance). Engine evidence is verifiable in the shipped build; repro steps are deterministic.