Remove NamedPipe helpers; make binary serializer transport-agnostic
Removed NamedPipe-specific serializer/deserializer helpers from the framework. Refactored tests to manage NamedPipe lifecycle directly using generic PipeWriter/PipeReader APIs. Introduced a transport-agnostic async deserialization method for any PipeReader. Updated XML docs and method signatures to clarify usage and flush strategies. All NamedPipe logic is now test-only; the core binary serializer is fully transport-agnostic. Minor test cleanups included.
Refactor AsyncPipeWriterOutput for stream compatibility
- Reduce test chunk size to 256 bytes and update test names/comments
- Add sender-side diagnostic logging and unify with receiver logs
- Detect StreamPipeWriter at runtime and enforce sequential flush/acquire for streams
- Retain parallelism for pipe-based writers (Kestrel/SignalR)
- Add DEBUG-only diagnostics at key chunking points
- Minor code style cleanups and doc clarifications
- Add Bash command to fetch StreamPipeWriter.cs for reference
Loretta