Remove SegmentBufferReader; unify on AsyncPipeReaderInput
Migrates all SignalR chunked streaming receive logic to AsyncPipeReaderInput, fully removing SegmentBufferReader and SegmentBufferReaderInput from the codebase. Updates all references, deserialization paths, and documentation to reflect the new unified primitive. Marks ADR-0003 as accepted (partially executed), closes related TODOs, and clarifies protocol docs. Sets DoubleBuffered as the default FlushPolicy. No wire format or behavioral changes; all tests pass.
Add ADR-0003: AcBinary streaming receive unification
- Add cross-cutting ADR-0003 for AsyncPipeReaderInput and transport-agnostic streaming helpers (NamedPipe, FileStream)
- Update BINARY and SIGNALR_BINARY_PROTOCOL docs to reference ADR-0003
- Add migration TODOs for each ADR-0003 step with acceptance criteria
- Add project ADR-0001 (binary projection serialization) and index
- Clarify buffer sizing and ADR refs in SegmentBufferReader docs
- Migrate JWT key/token log issues from LOGGING to new AUTH topic per ADR
- Update ADR template and improve doc formatting throughout
Loretta