.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

VocaluxeLib/CEncoding.cs

@@ -15,28 +15,37 @@
 // along with Vocaluxe. If not, see <http://www.gnu.org/licenses/>.
 #endregion
 
+using System;
+using System.Globalization;
 using System.Text;
 
 namespace VocaluxeLib
 {
-    static class CEncoding
+    public static class CEncoding
     {
+        static CEncoding()
+        {
+            Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
+        }
+
+        public static Encoding Locale => OperatingSystem.IsWindows() ? Encoding.GetEncoding(CultureInfo.CurrentCulture.TextInfo.ANSICodePage) : Encoding.UTF8;
+
         public static Encoding GetEncoding(this string encodingName)
         {
             switch (encodingName)
             {
                 case "AUTO":
-                    return Encoding.Default;
+                    return Locale;
                 case "CP1250":
                     return Encoding.GetEncoding(1250);
                 case "CP1252":
                     return Encoding.GetEncoding(1252);
                 case "LOCALE":
-                    return Encoding.Default;
+                    return Locale;
                 case "UTF8":
                     return Encoding.UTF8;
                 default:
-                    return Encoding.Default;
+                    return Locale;
             }
         }