.NET10 Migration (#946)

Runtime and build
- Move all projects to .NET 10 with SDK-style project files and a shared
  Directory.Build.props (WIN/LINUX, x86/x64 defines)
- Load managed and unmanaged dependencies from libs/managed and
  libs/unmanaged through assembly and native library resolvers
- Compile party modes with Roslyn instead of CodeDom
- Update AppVeyor to the .NET 10 SDK and dotnet test
- Download the FFmpeg and gstreamer runtimes from the dependencies
  repository during the build
- Remove the VC++ 2015-2022 runtime check, no dependency needs it anymore

Graphics and windowing
- Replace the Direct3D 9 renderer with Direct3D 11 (Vortice)
- Pace Direct3D 11 frames with a frame latency waitable swap chain
- Move window, input and message boxes to SDL3
- Replace System.Drawing with SkiaSharp and WinForms with SDL3 and a
  software renderer

Video and audio
- Replace Acinerella with FFmpeg 8.1.3 (FFmpeg.AutoGen)
- Add hardware accelerated video decoding (D3D11VA, DXVA2, VideoToolbox,
  VAAPI, VDPAU) with software fallback
- Convert YUV video frames to RGB on the GPU in Direct3D 11 and OpenGL
- Add the video options HardwareDecoding, GpuColorConversion,
  DecoderThreads and VideoDownscaleResolution
- Update OpenAL to OpenTK 4 and NAudio recording to WasapiRecorder

Fixes
- Fix the song preview start and shorten the reporter buttons
- Fix a crash when opening the highscore without a selected song
- Use the options slide highlight in the party mode screens to avoid
  brightness flicker on VRR displays
- Disable GameInput in the x86 build, SDL3 crashes in GameInputCreate
  on 32-bit systems with the GameInput runtime installed
- Fix a truncation warning in PitchTracker

makefile

@@ -2,14 +2,13 @@ ARCH?=$(shell uname -m | sed -e s/i.86/x86/ -e s/x86_64/x64/)
 windowsLibs = Output/gstreamer-sharp.dll Output/glib-sharp.dll
 all:
 	$(MAKE) -C PitchTracker
-	$(MAKE) -C Vocaluxe/Lib/Video/Acinerella
 	rm -f $(windowsLibs)
-	xbuild /property:Platform=$(ARCH) /property:Configuration=ReleaseLinux
+	dotnet build Vocaluxe/Vocaluxe.csproj -p:Platform=$(ARCH) -c ReleaseLinux
+	for project in PartyModes/*/*.csproj; do dotnet build $$project -c ReleaseLinux || exit 1; done
 
 clean:
-	xbuild /target:Clean
+	dotnet clean Vocaluxe/Vocaluxe.csproj -p:Platform=$(ARCH) -c ReleaseLinux
 	$(MAKE) -C PitchTracker clean
-	$(MAKE) -C Vocaluxe/Lib/Video/Acinerella clean
 	git checkout $(windowsLibs)
 
 INSTALLPATH?=/usr/share/vocaluxe