feat(notification): replace MessageBox with Windows toast notifications

[CalvinAllen]

Summary

Replace the current MessageBox.Show() notification with Windows toast notifications for a less intrusive experience.

Motivation

The current MessageBox:

• Steals focus from other applications
• Blocks interaction until dismissed
• Can be disruptive when multitasking

Toast notifications would:

• Appear in the bottom-right corner without stealing focus
• Auto-dismiss after a few seconds
• Allow clicking to bring VS to foreground
• Be visible even when VS is minimized

Implementation

Use Microsoft.Toolkit.Uwp.Notifications NuGet package:

new ToastContentBuilder()
    .AddText("Breakpoint Hit!")
    .Show();

Settings

Add a toggle option for notification style:

• MessageBox (current behavior)
• Toast notification
• Both (for users concerned about Windows DND mode suppressing toasts)

Considerations

• Need to add NuGet package dependency
• Could include action buttons ("Dismiss" / "Go to Breakpoint")
• Should work on Windows 10/11