Update sample webapp to mirror MAUI app features and structure

[Copilot]

This PR transforms the sample webapp to be a direct mirror of the MAUI app, implementing all the same features, pages, controls and functionality while using the shared Library project for business logic.

Changes Made

🎯 Core Requirements

• Direct Mirror: Webapp now has identical features, pages, controls and functionality as MAUI app
• Library Integration: Uses DeviceTestingKitApp.Library project for shared ViewModels and business logic
• Same Structure: Mirrors MainPage.xaml layout and component hierarchy exactly
• Identical Functionality: Counter behavior, display logic, and user interactions match perfectly

🔧 Technical Implementation

Project Dependencies

• Added reference to DeviceTestingKitApp.Library project
• Updated Program.cs with same service registration pattern as MauiProgram.cs

ViewModels Integration

• Uses MainViewModel and CounterViewModel from Library project
• Proper MVVM pattern with INotifyPropertyChanged support
• Same business logic and RelayCommand usage as MAUI app

Blazor Components

• Created CounterView.razor as Blazor equivalent of MAUI CounterView.xaml
• Implements same counter text logic: "Click me!" → "Clicked X time" → "Clicked X times"
• Proper data binding with property change notifications

Platform-Specific Services

• Implemented BlazorSemanticAnnouncer for web-specific accessibility
• Adapts ISemanticAnnouncer interface for web platform using JavaScript interop

UI Structure
Updated Home.razor to mirror MainPage.xaml exactly:

• .NET bot image with same alt text
• "Hello, World!" heading with semantic styling
• "Welcome to .NET Multi-platform App UI" subheading
• Counter component with identical layout and behavior

🧪 Verification

• ✅ Solution builds successfully
• ✅ Webapp builds and runs without errors
• ✅ All dependencies resolved correctly
• ✅ Counter functionality works identically to MAUI app
• ✅ Uses shared Library project as required
• ✅ Maintains consistent MVVM architecture

The webapp is now a complete direct mirror of the MAUI app, sharing the same ViewModels and business logic while providing web-specific UI implementations.

Fixes #85.

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[mattleibow]

This is ok, but we should copy the Maui way and have a razor class library for the Blazor things - just like we have a maui library for the Maui things.

Make sure we have the same sort of projects.

Also, we need to use the same sort of file structure as the Maui library. Controls, converters, features.

[Copilot]

This is ok, but we should copy the Maui way and have a razor class library for the Blazor things - just like we have a maui library for the Maui things.

Make sure we have the same sort of projects....

Created DeviceTestingKitApp.BlazorLibrary project that mirrors the MAUI library structure with the same folders: Controls/, Converters/, Features/. Moved all Blazor-specific components from the webapp to this new library and updated all references. The architecture now matches the MAUI pattern exactly. See commit 96f4a3c.

[mattleibow]

Let's use those live regions as you suggest.

[Copilot]

Implemented ARIA live regions for proper accessibility announcements. Created a JavaScript function that uses a visually hidden live region element with aria-live="polite" to announce messages to screen readers instead of console.log. See latest commit.