Updated test and benchmark project dependencies to latest versions (BenchmarkDotNet, coverlet.collector, MSTest, etc.). Reformatted source generator project references for consistency. Commented out most AcBinary benchmark variants in Program.cs, leaving only FastMode+Default enabled. Significantly expanded README with detailed architecture, file descriptions, and configuration for each serializer subfolder. Added LLM maintenance notes to ensure documentation stays in sync with code changes.
- Updated all projects to use `Newtonsoft.Json` v13.0.3 for consistency.
- Introduced `HybridReferenceResolver` for semantic and numeric ID handling.
- Refactored `SerializeObjectExtensions` to support deep JSON merging.
- Simplified `IId<T>` interface by removing `IEquatable<T>` constraint.
- Improved `AcSignalRDataSource` with robust `AddRange` and `CopyTo` methods.
- Added `JsonExtensionTests` for deep hierarchy, reference, and edge cases.
- Implemented `UnifiedMergeContractResolver` for custom JSON behavior.
- Optimized type/property caching with `TypeCache` and `CachedPropertyInfo`.
- Enhanced SignalR integration to fix primitive array deserialization issues.
- Introduced `JsonNoMergeCollection` attribute for replace-only collections.
- Added test DTOs and `TestDataFactory` for real-world scenario simulations.
- Improved performance with `ConcurrentDictionary` and `ObjectPool`.
- Fixed `$id`/`$ref` handling for non-semantic references and arrays.