Implement BlackMagic ATEM integration with real-time preview/program monitoring

[Copilot]

Overview

This PR implements integration with BlackMagic ATEM video switchers, enabling real-time monitoring of Preview and Program inputs directly from HueCue's status bar.

Changes

Core ATEM Connection Service

• New AtemConnection.cs: Complete UDP-based ATEM protocol implementation
  • Handshake and connection management
  • Real-time packet parsing for Preview (PrvI) and Program (PrgI) commands
  • Automatic ACK handling
  • Event-driven architecture with Connected, Disconnected, PreviewInputChanged, and ProgramInputChanged events
  • Comprehensive input source mapping (40+ standard ATEM sources including Cameras, Media Players, Color sources, etc.)

ViewModel Integration

• Added three new observable properties to MainWindowViewModel:
  • AtemPreviewInput - Current preview input name
  • AtemProgramInput - Current program input name
  • AtemConnected - Connection status
• Added ConnectToAtemCommand for toggling ATEM connection
• Thread-safe event handlers using Application.Current.Dispatcher.Invoke to marshal updates from background UDP thread to UI thread
• Proper cleanup in Dispose() method

UI Updates

• File Menu: Added "Connect to ATEM" menu item that dynamically changes to "Disconnect from ATEM" when connected
• Status Bar: Added ATEM Preview and Program displays with smart visibility (hidden when not connected)
• Professional layout with separators between status items

Testing

• New AtemConnectionTests.cs with unit tests for connection initialization, disposal, and cleanup
• Updated MainWindowViewModelTests.cs to include ATEM properties in existing tests
• All tests pass and follow existing patterns

Documentation

• Updated README with ATEM integration in features list
• Added usage instructions
• Updated technical details to mention ATEM protocol implementation

Configuration

• Default ATEM IP: 192.168.10.240 (can be modified in code)
• Port: 9910 (standard ATEM control port)
• Protocol: UDP

Example Usage

1. Launch HueCue
2. File → Connect to ATEM
3. Status bar shows: "ATEM Preview: Camera 1 | ATEM Program: Camera 2"
4. Switch inputs on your ATEM - status bar updates in real-time!
5. File → Disconnect from ATEM to disconnect

Technical Implementation

The implementation uses a background thread for UDP communication with proper thread synchronization:

• UDP socket on background thread handles packet receive loop
• Events raised from background thread
• UI updates marshaled to UI thread via Dispatcher.Invoke
• Async/await pattern for non-blocking connection
• Proper resource cleanup with IDisposable

Dependencies

No additional dependencies required - implementation uses only standard .NET networking libraries.

Testing Notes

While unit tests are included, manual testing on Windows with an actual ATEM switcher is recommended to verify:

• Connection success/failure handling
• Real-time preview/program updates
• Graceful disconnection
• Proper cleanup on app close

Fixes #41

Original prompt

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This section details on the original issue you should resolve

<issue_title>Implement BlackMagic ATEM integration</issue_title>
<issue_description>Implement integration connecting to a black magic ATEM.

Include UI status bar updates showing with scene is preview and which is program.

A sample of doing this integration can be found in this repository. https://github.com/LibAtem/LibAtem</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #41

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[Keboo]

@copilot Remove this reference and all usages.

[Copilot]

Removed log4net package reference from both Directory.Packages.props and HueCue.csproj. The package was not being used in the code. (commit 6eb8d2c)