BF16 att_sums and ffw_out
Support BF16 B views without decompression
Support arbitrary types in MulByConstAndAdd, AddFrom
Also update profiler annotations in ops-inl.h
PiperOrigin-RevId: 766995010
This replaces per-weight instantiations of all code with only per-MatMul/norm.
Reduces binary size by 133KiB.
WeightsOwner is no longer required for type erasing, hence it is replaced with ModelWeightsPtrs.
Also remove unused EmbedToken, replaced with EmbedMMToken.
PiperOrigin-RevId: 766497657
Precompute row pointers.
Remove no longer used MHA support; QStride -> qkv_dim.
Remove RowPtr from MatMul interface, use only MatPtrT.
Require opt-in define for NUQ to speed up builds.
Also fix io.cc on Windows.
PiperOrigin-RevId: 766228108