Separate raw and framed streaming in AcBinarySerializer
Refactored AcBinarySerializer and AsyncPipeWriterOutput to support both raw (headerless) and multiplexed/framed ([201][UINT16][data]) streaming wire formats, controlled by a new flag and explicit APIs. Updated AsyncPipeReaderInput and AcBinaryDeserializer to match, with new constructor options and documentation. Expanded tests for both modes and added runtime type detection for flush strategy safety. Minor refactoring and doc improvements throughout.
Refactor SIGDS docs, archive DEC log, add pipe tests
- Updated all references to AcSignalRDataSource docs to new SIGNALR_DATASOURCE/README.md location; introduced SIGDS topic and paired issues/TODO files.
- Implemented new Decision Log archival policy: last-15-active entries remain, older entries moved to year-month archive (LLMP-DEC-65, 67); updated docs-archive skill for two-rule rotation.
- Added new SIGDS architectural TODO (ACCORE-SIGDS-T-D9F2) for relocating DataSource code.
- Updated doc tables, glossaries, and conventions for SIGDS.
- Added AcBinarySerializerPipeParallelTests.cs for parallel serialization/deserialization round-trip tests.