Fix ALG crash on multi-scene: tensor 'or' in alg_latents (True,True) fallback

sample_funpack_distilled_flow built the alg_latents dict eagerly, and the
(True, True) value used 'anchor_blurred or tail_blurred' as its fallback when
both_blurred was None. When anchor blur is on but tail blur is off (or the tail
blur returned None), anchor_blurred is a multi-element tensor, so 'or' calls
bool() on it -> 'Boolean value of Tensor with more than one value is ambiguous'.

Surfaces only on continuation scenes: an anchorless first scene (identity/empty
latent, no denoise_mask) skips ALG entirely, but a later scene with a guide mask
enters ALG and trips the eager dict build. Replaced the tensor 'or' with explicit
None chaining (both -> anchor -> tail). Pure fallback; when (True,True) is actually
indexed both blurs are on, so both_blurred is non-None and the singles are never
reached. Independent of taste_nearest_prompt, which was merely on in the same run.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

samplers.py

@@ -1869,7 +1869,15 @@ def sample_funpack_distilled_flow(model, x, sigmas, extra_args=None, callback=No
             (False, False): alg_sharp_latent_image,
             (True, False): anchor_blurred,
             (False, True): tail_blurred,
-            (True, True): both_blurred if both_blurred is not None else (anchor_blurred or tail_blurred),
+            # both → anchor → tail → None. Explicit None checks, NOT `anchor_blurred or
+            # tail_blurred`: `or` calls bool() on the first operand, which is a multi-element
+            # tensor when anchor blur is on but tail blur is off (both_blurred is then None) —
+            # "Boolean value of Tensor is ambiguous". This value is only a defensive fallback:
+            # when (True, True) is actually indexed, alg_anchor_on and alg_tail_on are both
+            # True, so both_blurred is non-None and the chain never reaches the singles.
+            (True, True): (both_blurred if both_blurred is not None
+                           else anchor_blurred if anchor_blurred is not None
+                           else tail_blurred),
         }
         alg_active = alg_anchor_on or alg_tail_on
     if alg_active: