Implements per-block DiT activation steering as an alternative to textual
inversion. Extractor runs frozen generator on dataset with BJ vs empty
conditions, records mean hidden-state delta per block, saves [hidden_dim]
vectors (seq-averaged so they broadcast to any inference duration). Loader
reads the bundle. Sampler registers forward hooks during the ODE that add
strength × vec to each block output, cleaned up in a finally block.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
