AI Shell Preview 4 Release!

- Improved macOS support with iTerm2 for a better side car experience when running PowerShell 7.
- Added support for Entra ID authentication to Azure OpenAI instances for enhanced security.
- New parameters added to Invoke-AIShell command for easier usage of the side pane without switching between screens.
- Introduction of an offline AI agent using the Phi Silica model for an offline AI Shell experience.
- Instructions for locally building AI Shell provided, with a warning of potential breaking changes in future releases.
- Installation instructions for AI Shell Preview 4 provided, along with a call for feedback on GitHub repository.