release: switch to embedded debug info, drop snupkg push

nuget.org's snupkg-validation rejected every symbol package this
repo pushed (the .nupkg lands fine; the .snupkg flatcontainer URL
returns 404 after async validation). Root cause: side-PDBs from
build tools (Grpc.Tools / Confluent.Kafka / etc.) land in the
snupkg but not the nupkg, so the PDB<->DLL match check fails.

Fix mirrors the Bowire-monorepo convention:
  Directory.Build.props
    DebugType=portable + IncludeSymbols=true + SymbolPackageFormat=snupkg
    -> DebugType=embedded + IncludeSymbols=false. PDB lands inside
    the main DLL, SourceLink step-through stays available.

  .github/workflows/release.yml
    dotnet nuget push *.snupkg step removed.

Author: thomas-stegemann

.github/workflows/release.yml

@@ -55,9 +55,10 @@ jobs:
         if: ${{ !contains(github.ref, '-rc') && env.NUGET_API_KEY != '' }}
         env:
           NUGET_API_KEY: ${{ secrets.NUGET_API_KEY }}
+        # No separate .snupkg push — Directory.Build.props uses
+        # DebugType=embedded so debug info ships inside the .nupkg.
         run: |
           dotnet nuget push "artifacts/packages/*.nupkg"             --source https://api.nuget.org/v3/index.json             --api-key "$NUGET_API_KEY"             --skip-duplicate
-          dotnet nuget push "artifacts/packages/*.snupkg"             --source https://api.nuget.org/v3/index.json             --api-key "$NUGET_API_KEY"             --skip-duplicate
 
       - name: Create GitHub Release
         uses: softprops/action-gh-release@v3

Directory.Build.props

@@ -61,9 +61,14 @@
   <PropertyGroup>
     <PublishRepositoryUrl>true</PublishRepositoryUrl>
     <EmbedUntrackedSources>true</EmbedUntrackedSources>
-    <DebugType>portable</DebugType>
-    <IncludeSymbols>true</IncludeSymbols>
-    <SymbolPackageFormat>snupkg</SymbolPackageFormat>
+    <!-- Embedded debug info: PDB ships inside the assembly itself,
+         so SourceLink + step-through debugging work without a
+         separate .snupkg. Matches the Bowire-monorepo convention and
+         sidesteps nuget.org's snupkg-validation chain (which
+         consistently rejected our snupkgs because of side-PDBs from
+         build tools like Grpc.Tools / Confluent.Kafka). -->
+    <DebugType>embedded</DebugType>
+    <IncludeSymbols>false</IncludeSymbols>
   </PropertyGroup>
 
   <ItemGroup Condition="'$(IsPackable)' != 'false'">