CI: build with the .NET 10 SDK

Roslyn 5.3.0 packages (asset-handles generator) ship analyzers built
against compiler 4.12+, which the SDK 8 toolchain cannot load (CS9057).
The target framework stays net8.0; CLAUDE.md documents the SDK floor.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.github/workflows/ci.yml

@@ -10,9 +10,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+      # Сборка требует SDK 10+: Roslyn-пакеты 5.3.0 (генератор ассет-хендлов)
+      # не загружаются компилятором из SDK 8. TargetFramework остаётся net8.0.
       - uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: 8.0.x
+          dotnet-version: 10.0.x
       - name: Build
         run: dotnet build MrGameEng.sln --configuration Release
       - name: Test