Update strip iteration suffix behavior

tests/test_dumas_json_nodes.py

@@ -57,12 +57,19 @@ class DumasJSONNodeTests(unittest.TestCase):
 
         self.assertEqual(result, ("asset_build",))
 
-    def test_strip_iteration_suffix_leaves_names_without_numeric_suffix_unchanged(self):
+    def test_strip_iteration_suffix_removes_last_underscore_segment_even_when_not_numeric(self):
         node = DumasStripIterationSuffixNode()
 
         result = node.strip_iteration_suffix("my_asset_final.png")
 
-        self.assertEqual(result, ("my_asset_final.png",))
+        self.assertEqual(result, ("my_asset.png",))
+
+    def test_strip_iteration_suffix_leaves_names_without_underscore_unchanged(self):
+        node = DumasStripIterationSuffixNode()
+
+        result = node.strip_iteration_suffix("char123.png")
+
+        self.assertEqual(result, ("char123.png",))
 
     def test_slugify_string_normalizes_text(self):
         node = DumasSlugifyStringNode()