sampler: name the guide mechanism on each scene's timing line

The per-scene line now includes run_mechanisms, so a slow guide scene
attributes itself fully: which feature appended the tokens
(custom_guide_stack / carry_i2v_guides / joyai_memory / mid_scene_guide
/ soft_continuation) alongside the tail counts and sampling seconds.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

samplers.py

@@ -4283,6 +4283,7 @@ class FunPackLTXAVSceneChainSampler:
                 (f", carried={carried + soft_carried}f" if (carried + soft_carried) > 0 else "")
                 + (f", guide_tail={guide_tail}f" if guide_tail > 0 else "")
                 + (f", audio_tail={audio_tail}f" if audio_tail > 0 else "")
+                + (f" [{', '.join(run_mechanisms)}]" if run_mechanisms else "")
             )
             print(f"[FunPackSceneChain] Scene {scene_index + 1}: sampling {_scene_sample_s:.1f}s{_scene_extras}")
             report_lines.append(