Terminal crashes with Exit 126 and unsigned script errors on Windows 11 Enterprise

### Short summary

The GitHub Copilot Desktop integrated terminal fails to initialize in locked-down Windows 11 Enterprise environments. The application attempts to force-inject an unsigned PowerShell script (shellIntegration.ps1), which is blocked by system security policies. Additionally, standard MSYS2/MinGW64 binaries crash with Exit Code 126 because the app passes the project directory as an execution argument rather than a working directory context.

### Affected version or release

v1.1.11

### Installation context

Windows 11 Enterprise; MSYS2 / MinGW64 (standard installation at C:\msys64); local git worktrees

### What happened?

- _Security Error:_ PowerShell blocks `shellIntegration.ps1` because it is not digitally signed, triggering an UnauthorizedAccess exception due to corporate Execution Policies.
- _Execution Crash:_ Pointing the terminal to `bash.exe` or `mingw64.exe` results in a crash with `Exit Code 126 ("Is a directory")`. **The shell attempts to execute the repository folder path passed as a command-line argument.**
- _Architecture Mismatch:_ Attempts to use custom-compiled C# wrappers often result in `OS Error 193 ("%1 is not a valid Win32 application")` if there is any mismatch in the background process host architecture.

### Steps to reproduce

1. Open GitHub Copilot Desktop on **Windows 11 Enterprise.**
2. Navigate to a project folder _(e.g., C:\Users\user\github\)_
3. Set the custom terminal path to `C:\msys64\mingw64.exe`
4. Open the integrated terminal panel.
5. Observe the crash _(Exit 126)_ or the red PowerShell script-signing error text.

### Expected behavior

The terminal should open a clean, interactive MinGW64 shell initialized at the project's root directory without attempting to run the directory as a command or triggering unsigned script blocks.

### Additional context

_!! Resolution / Workaround (The "Stub" Method): !!_

**The issue is fully resolved by utilizing Windows Terminal as a bridge, which handles the initialization sequence outside of Copilot's restrictive process manager.**

1. Create Custom Profile: In Windows Terminal, create a new profile (e.g., named git-bash).
2. Set Command Line: Set the command line to C:\msys64\mingw64.exe
3. Set as Default: In Windows Terminal startup settings, set this new profile as the Default profile.
4. Launch via Copilot: GitHub Copilot Desktop now spawns a "dummy/stub" via Windows Terminal, which successfully opens the native MSYS2 window without crashing.

Commencez par reproduire l’échec avec C:\msys64\mingw64.exe sous Windows 11 Enterprise, puis suivez le chemin de lancement du terminal intégré et sa gestion de shellIntegration.ps1. Le travail est terminé lorsqu’un shell MinGW64 interactif s’ouvre à la racine du projet sans traiter le répertoire comme une commande ni déclencher de blocage des scripts non signés.

Rédigé par le modèle d'indexation à partir du texte de l'issue.