Fix tracer_via_instance_from to include scaling_galaxies

Replace early-return + operator merge with list accumulation so both
extra_galaxies and scaling_galaxies are always passed to the Tracer.
The old pattern dropped scaling_galaxies when extra_galaxies was present
due to integer-key collision in af.Collection +.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: 2 people

autolens/analysis/analysis/lens.py

@@ -113,14 +113,18 @@ def tracer_via_instance_from(
         else:
             cosmology = self.cosmology
 
+        galaxy_list = list(instance.galaxies)
+
         if hasattr(instance, "extra_galaxies"):
             if getattr(instance, "extra_galaxies", None) is not None:
-                return Tracer(
-                    galaxies=instance.galaxies + instance.extra_galaxies,
-                )
+                galaxy_list += list(instance.extra_galaxies)
+
+        if hasattr(instance, "scaling_galaxies"):
+            if getattr(instance, "scaling_galaxies", None) is not None:
+                galaxy_list += list(instance.scaling_galaxies)
 
         return Tracer(
-            galaxies=instance.galaxies,
+            galaxies=galaxy_list,
             cosmology=cosmology,
         )