Febris Simulation SDK v0.1.0

Native C++ SDK for Windows x64: FebrisSimApi.h (flat extern "C" ABI, version 1) plus the DLL and import library. Byte-parity verified against the C# SDK at this tag by the conformance harness in this repository. Verify the download against SHA256SUMS. The C# SDK for the same tag ships via NuGet (see pack.yml).