.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

appveyor.yml

@@ -1,7 +1,7 @@
 version: '{build}'
 pull_requests:
   do_not_increment_build_number: true
-image: Visual Studio 2022
+image: Visual Studio 2026
 configuration: ReleaseWin
 platform:
 - x64
@@ -34,7 +34,6 @@ install:
     else{
         $Env:TAG_NAME_WITH_BRANCH_NAME_FALLBACK = $Env:APPVEYOR_REPO_BRANCH
     }
-    choco install "opencover.portable" -y
     Install-Product node 24 x64
     node --version
 before_build:
@@ -60,7 +59,7 @@ before_build:
         Write-Warning "Theme-Video download failed"
     }
     
-    nuget restore -DisableParallelProcessing
+    msbuild Vocaluxe.sln /t:Restore /p:Configuration=$Env:CONFIGURATION /p:Platform=$Env:PLATFORM /verbosity:minimal
     
     if($Env:MAIN_REPO -and ($Env:PLATFORM -eq 'x64'))
     {
@@ -95,8 +94,6 @@ build:
   verbosity: normal
 after_build:
 - ps: |
-    ./.appveyor/runGitLink.ps1
-    
     cd Output   
 
     $forkBuildTag = ""
@@ -119,14 +116,20 @@ after_build:
     }
 test_script:
 - ps: |
-    if (($Env:MAIN_REPO) -and ($Env:PLATFORM -eq 'x64') -and ($Env:APPVEYOR_PULL_REQUEST_NUMBER -or $Env:APPVEYOR_REPO_BRANCH -eq 'develop')){
-        OpenCover.Console.exe -register:user -target:"nunit3-console.exe" -targetargs:".\Tests\bin\Release\Tests.dll --result=.\TestResult.xml;format=AppVeyor" -output:".\CoverageResult.xml"
+    if ($Env:PLATFORM -eq 'x64'){
+        $testResult = Join-Path $Env:APPVEYOR_BUILD_FOLDER "TestResult.xml"
+        if (($Env:MAIN_REPO) -and ($Env:APPVEYOR_PULL_REQUEST_NUMBER -or $Env:APPVEYOR_REPO_BRANCH -eq 'develop')){
+            dotnet test .\Tests\Tests.csproj --no-build -c $Env:CONFIGURATION -p:Platform=$Env:PLATFORM --logger "nunit;LogFilePath=$testResult" --logger Appveyor --collect:"XPlat Code Coverage;Format=opencover" --results-directory .\TestResults
+            Get-ChildItem .\TestResults -Recurse -Filter "coverage.opencover.xml" | Select-Object -First 1 | Copy-Item -Destination .\CoverageResult.xml
+        }
+        else{
+            dotnet test .\Tests\Tests.csproj --no-build -c $Env:CONFIGURATION -p:Platform=$Env:PLATFORM --logger "nunit;LogFilePath=$testResult" --logger Appveyor
+        }
+        $testExitCode = $LASTEXITCODE
+        if ($testExitCode -ne 0){
+            exit $testExitCode
+        }
     }
-    else{
-        nunit3-console.exe ".\Tests\bin\Release\Tests.dll" --result=".\TestResult.xml;format=AppVeyor"
-    }    
-    $wc = New-Object 'System.Net.WebClient'
-    $wc.UploadFile("https://ci.appveyor.com/api/testresults/nunit3/$($env:APPVEYOR_JOB_ID)", (Resolve-Path .\TestResult.xml))
 
 after_test:
 - ps: |