feat(windows): add Windows sender with VDD and ADB support

[ayufan]

Summary

• add a .NET 8 WPF sender for Windows with mirror and VDD-backed extended display modes
• support receiver discovery over mDNS, manual endpoints, and direct Android USB/ADB sessions
• add FFmpeg capture/encoding, input injection, diagnostics, preferences, and tray lifecycle management
• document Windows dependencies, VDD setup, connection modes, and build workflow

Validation

• git diff --check upstream/main...HEAD
• the project has been compiled and core sharing workflows have been exercised on Windows
• this macOS host cannot independently rerun the WPF build because its .NET SDK does not include Microsoft.NET.Sdk.WindowsDesktop