flux-v2 v4 rev: fix attn_bias+ControlNet conditioning bug (multiply 0.35), bfl-lora to BFL spec (guidance 10, LoRA 0.85), calibration-validated

flux-v2 rev: generic anatomy prompt as default positive, reusable negative node (inert at CFG 1.0, documented)

Promote flux-v2 workflows to workflows/: sweep-validated defaults (guidance 3.0/4.0, 896x1152 portrait pre-pass, saved crops, hires group), full 84-run matrix passed on inputs_v2