…oke-AIShell -PostCode` (#361)

This PR fixes the following scenarios on macOS
1. Running `/code post` from the `AIShell` pane to post code to the `PowerShell` pane
2. Running `Invoke-AIShell -PostCode` from the `PowerShell` to request code to be posted from the `AIShell` pane.

**[NOTE]** Now the `AIShell` module depends on the **v2.4.2-beta2** PSReadLine, because a private field was added in PSReadLine to accurately indicate if PSReadLine is initialized and ready to render (PowerShell/PSReadLine#4706).

The `AIShell` module starts to depend on that field to be more deterministic about if PSReadLine is running and ready. Before this change, we relied on `Console.TreatControlCAsInput` which is not accurate and may cause race condition: `Console.TreatControlCAsInput` is set to true, but `Initialize(...)` is not called yet. Rendering the posted code before initialization could result in corrupted state -- posted code may be rendered on wrong position or even cause exception.

… the `@` operator (#372)

…374)

…nt` (#351)

- Add the `model` command for model management
- Add the `system-prompt` command to configure `SystemPrompt` with the selected model.
- Add the `preset` command for preset management