alg_blur_guides no longer borrows the sampler's anchor knobs: the Scene Chain
Sampler gains alg_guide_blur_strength (default 2.0) and
alg_guide_blur_sigma_threshold (default 0.975), threaded per-chunk via
extra_options like the tail count. The sampler now precomputes one latent per
(anchor blurred?, tail blurred?) combination — the frame sets are disjoint, so
the both-blurred variant composes the two passes — and each region follows its
own sigma window per step. Anchor ALG (alg_enabled/alg_strength/
alg_sigma_threshold) is untouched and back to anchor-only semantics.
Editor: 'Guide blur strength' and 'Guide blur sigma threshold' rows appear
under Engine ▸ Experimental when the blur toggle is on (sampler_inputs bridge,
names match the new node widgets; inputs appended at the block end to keep the
builder's positional widget mapping aligned).
Verified live: object_info shows both widgets appended last; Editor rows
appear on toggle and persist to project.sampler_inputs. 11 ALG unit tests
pass (new: composed independent-strength blur); same 20 pre-existing suite
failures.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
