Major overhaul of binary serialization:
- Rewrote AcBinarySerializer as a static, optimized, feature-rich serializer with VarInt encoding, string interning, property name tables, reference handling, and optional metadata.
- Added AcBinaryDeserializer with matching features, including merge/populate support and robust error handling.
- Introduced AcBinarySerializerOptions and AcSerializerOptions base class for unified serializer configuration (JSON/binary).
- Added generic extension methods for "any" serialization/deserialization based on options.
- Updated tests and benchmarks for new APIs; fixed null byte code and added DateTimeKind test.
- Fixed namespace typos and improved code style and documentation.