Publish to NuGet and update D-ID + Simli to use package reference

Summary

The tryAGI.RealtimeAvatar.Abstractions NuGet package needs to be published so that D-ID and Simli SDKs can reference it via <PackageReference> instead of maintaining local copies of IRealtimeAvatarClient.cs.

Current State

• dotnet pack works and produces tryAGI.RealtimeAvatar.Abstractions.1.0.0.nupkg
• No CI/CD workflows exist yet (no .github/workflows/ directory)
• Three copies of IRealtimeAvatarClient.cs exist:
  • Canonical: tryAGI/RealtimeAvatar/src/libs/RealtimeAvatar/IRealtimeAvatarClient.cs
  • Simli: tryAGI/Simli/src/libs/Simli/Extensions/IRealtimeAvatarClient.cs (identical)
  • D-ID: tryAGI/DId/src/libs/DId/Extensions/IRealtimeAvatarClient.cs (minor drift: 2 extra #pragma warning disable lines)

Steps to Complete

1. Set up CI/CD for NuGet publishing

• Add .github/workflows/ with a build + publish workflow (use HavenDV/workflows shared workflow pattern)
• Configure NuGet API key in repo secrets
• Use MinVer for versioning with v tag prefix

2. Publish to NuGet

• Tag a release (e.g., v0.1.0)
• Verify package appears on nuget.org

3. Update D-ID SDK

• Add <PackageReference Include="tryAGI.RealtimeAvatar.Abstractions" Version="<latest>" /> to src/libs/DId/DId.csproj
• Delete src/libs/DId/Extensions/IRealtimeAvatarClient.cs (the local copy)
• Build to verify: dotnet build DId.slnx
• Commit and push

4. Update Simli SDK

• Add <PackageReference Include="tryAGI.RealtimeAvatar.Abstractions" Version="<latest>" /> to src/libs/Simli/Simli.csproj
• Delete src/libs/Simli/Extensions/IRealtimeAvatarClient.cs (the local copy)
• Build to verify: dotnet build Simli.slnx
• Commit and push

Why This Matters

Using a shared NuGet package instead of local copies ensures type compatibility across SDKs — consumers that depend on both D-ID and Simli will get the same assembly-qualified IRealtimeAvatarClient type, enabling provider-agnostic code.

Missing from csproj (Nice-to-have)

• <PackageReadmeFile> — NuGet warns about missing README
• <PackageLicenseExpression> — License metadata
• <SignAssembly> with key.snk — Strong naming for consistency with other tryAGI packages
• <MinVerTagPrefix>v</MinVerTagPrefix> — MinVer versioning

Start with the canonical interface at tryAGI/RealtimeAvatar/src/libs/RealtimeAvatar/IRealtimeAvatarClient.cs, the DId.csproj and Simli.csproj files, and the existing package configuration. Add the requested workflow under .github/workflows, publish the package, then replace the local interface copies in DId and Simli with the package reference. Run dotnet build DId.slnx and dotnet build Simli.slnx, and verify the package appears on nuget.org.