Use centralized is_test_mode() from PyAutoFit

Replace direct os.environ PYAUTOFIT_TEST_MODE checks with the shared
is_test_mode() helper for consistency across the stack.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 2 people

autoarray/inversion/mesh/image_mesh/hilbert.py

@@ -12,6 +12,7 @@
 from autoarray.structures.grids.irregular_2d import Grid2DIrregular
 
 from autoarray import exc
+from autofit.non_linear.test_mode import is_test_mode
 
 
 def gilbert2d(width, height):
@@ -330,7 +331,7 @@ def check_mesh_pixels_per_image_pixels(
             an exception is raised.
         """
 
-        if os.environ.get("PYAUTOFIT_TEST_MODE") == "1":
+        if is_test_mode():
             return
 
         if image_mesh_min_mesh_pixels_per_pixel is not None:
@@ -397,7 +398,7 @@ def check_adapt_background_pixels(
             an exception is raised.
         """
 
-        if os.environ.get("PYAUTOFIT_TEST_MODE") == "1":
+        if is_test_mode():
             return
 
         if image_mesh_adapt_background_percent_threshold is not None: