0.9.0-preview.5

The packages are now OpenCodeDotNet.Sdk and OpenCodeDotNet.Sdk.Extensions, and the
repository lives in the opencode-dotnet organization. The API is unchanged: only the
PackageReference changes. The release also fixes thread-pool starvation from standalone servers
on Windows.

💥 Breaking changes

• The packages are now OpenCodeDotNet.Sdk and OpenCodeDotNet.Sdk.Extensions. Change the
  PackageReference from OpenCodeAI.Sdk and OpenCodeAI.Sdk.Extensions; the earlier ids receive
  no further versions. Assemblies and namespaces are still OpenCode.Sdk, so no source changes.
• The repository moved to
  opencode-dotnet/opencode-sdk-dotnet.
  GitHub redirects the old links. The nightly feed moved with it to
  https://nuget.pkg.github.com/opencode-dotnet/index.json; the earlier feed keeps its existing
  OpenCodeAI.* nightlies and receives no new ones.

🐛 Fixes

• A standalone server no longer holds two thread-pool threads on Windows. Process creates
  the redirected stdout and stderr pipes synchronous there before .NET 11, and its event readers
  blocked a pool thread on each for the server's whole life; with a few servers in one process the
  pool starved, and unrelated async work stalled for seconds. The launcher now reads both streams
  on dedicated threads on Windows, and disposal ends them: it waits for end-of-stream inside the
  drain bound and cancels a read still blocked, so no reader outlives the server handle. That also
  keeps the last lines of an exited child from missing the OpenCodeServerOutput snapshot under
  load. Linux and macOS are unchanged.