Pack SampSharp analyzer packages as Roslyn analyzers (not regular libs) - #570

Analyzer-oriented packages (SampSharp.SourceGenerator, SampSharp.Analyzer, SampSharp.CodeFixes) were being packed like normal libraries, so consumers did not get them under Dependencies → Analyzers. This updates package layout so NuGet/VS consume them as analyzers/source generators.

• Packaging layout corrected for analyzer consumption

  • Updated all three projects to stop packing build output into lib/*.
  • Explicitly pack each assembly into analyzers/dotnet/cs.

• Analyzer-package defaults aligned

  • Disabled symbol package output for these analyzer-only packages.
  • Disabled package analysis warnings that assume lib/ref assets for runtime libraries.

• Projects updated

  • src/SampSharp.Analyzer/SampSharp.Analyzer.csproj
  • src/SampSharp.SourceGenerator/SampSharp.SourceGenerator.csproj
  • src/SampSharp.CodeFixes/SampSharp.CodeFixes.csproj

<PropertyGroup>
  <IncludeBuildOutput>false</IncludeBuildOutput>
</PropertyGroup>

<ItemGroup>
  <None Include="$(OutputPath)$(AssemblyName).dll"
        Pack="true"
        PackagePath="analyzers/dotnet/cs"
        Visible="false" />
</ItemGroup>