Document IPC transport limitations for gRPC client-side load balancing and connectivity state

[Copilot]

Fixes #35871

The gRPC inter-process communication docs don't mention that IPC transports rely on SocketsHttpHandler.ConnectCallback, which disables client-side load balancing and connectivity state tracking. Users hit an opaque InvalidOperationException with no guidance. Per maintainer feedback, the note belongs on the shared xref:grpc/interprocess page since it applies to both Unix domain sockets and named pipes.

Changes

• Added a [!WARNING] block to aspnetcore/grpc/interprocess.md (Configure client and server section) covering:
  • Why the limitation exists (ConnectCallback requirement for custom endpoints).
  • Unavailable features: ServiceConfig.LoadBalancingConfigs, GrpcChannel.State, GrpcChannel.WaitForStateChangedAsync.
  • The InvalidOperationException text users encounter.
• Used code-style backticks rather than <xref:> for the Grpc.Net.Client APIs, since those types ship in the third-party grpc-dotnet package and aren't verifiable in the xref index.
• Updated ms.date and added ai-usage: ai-assisted metadata.

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Internal previews

📄 File	🔗 Preview link
aspnetcore/grpc/interprocess.md	aspnetcore/grpc/interprocess

[wadepickett]

Fixes #35871