feat(hpc): add CAM-PQ codec — Content-Addressable Memory as Product Quantization

Unifies FAISS PQ6x8 and CLAM 48-bit archetypes. 170x compression.
CamCodebook, DistanceTables (AVX-512 VPGATHERDD), PackedDatabase (stroke cascade),
3 training modes (geometric/semantic/hybrid). 14 tests passing.

https://claude.ai/code/session_01BTATTRUACijvsK4hqmKUBR

Author: AdaWorldAPI