Add C++ wrapper Simd::SynetInnerProduct32f

[ermig1979]

Summary

Adds a public C++ analogue of Synet::InnerProduct32f (src/Synet/Utils/InnerProduct.h in ermig1979/Synet) to the Simd Library.

• New class Simd::SynetInnerProduct32f in src/Simd/SimdSynet.hpp wrapping SimdSynetInnerProduct32fInit / SimdSynetInnerProduct32fInternalBufferSize / SimdSynetInnerProduct32fExternalBufferSize / SimdSynetInnerProduct32fSetParams / SimdSynetInnerProduct32fForward / SimdRelease.
• Doxygen description for the class (group cpp_synet).
• TestSynetInnerProduct32f() in src/Test/TestCheckCpp.cpp compares the wrapper with the C API (forward results, InternalBufferSize, ExternalBufferSize).
• docs/2026.html (release 7.2.165) and prj/txt/DoxygenGroups.txt updated.

src/Simd/SimdSynet.hpp is already listed in prj/vs2022/Simd.vcxproj and prj/vs2022/Simd.vcxproj.filters (added with Simd::SynetAdd16b).

Testing

• CMake Release build (g++, SIMD_SHARED=ON) of the library and Test.
• ./Test "-r=.." -cc=1 -fi=SynetInnerProduct32f -tt=1 -ts=1: CheckCpp (including TestSynetInnerProduct32f) and SynetInnerProduct32f C API tests finished successfully.
• Standalone check: Simd::SynetInnerProduct32f::Enable() is true; wrapper output matches the C API (0 mismatches on a 4x8x16 FP32 case with const B and bias) and naive C[0] (2.0840). Internal/external buffer sizes match the C API (128 / 0).