style: label Guanghan radiator panels

Co-Authored-By: Codex <noreply@openai.com>

tests/test_guanghan_topology_demo.py

@@ -54,6 +54,25 @@ class GuanghanTopologySourceTests(unittest.TestCase):
             r'<(?:g|rect)[^>]+class="[^"]*radiator[^"]*"[^>]+data-module=',
         )
 
+    def test_each_radiator_has_a_visible_text_label(self) -> None:
+        radiator_groups = re.findall(
+            r'<g class="radiator"[^>]*>(.*?)</g>',
+            self.html,
+            flags=re.S,
+        )
+        self.assertEqual(len(radiator_groups), 4)
+        for group in radiator_groups:
+            self.assertIn(">散热器</text>", group)
+            rect = re.search(r'<rect x="(\d+)" y="(\d+)" width="(\d+)"', group)
+            label = re.search(r'<text[^>]+x="(\d+)" y="(\d+)"[^>]*>散热器</text>', group)
+            self.assertIsNotNone(rect)
+            self.assertIsNotNone(label)
+            rect_x, rect_y, rect_width = map(int, rect.groups())
+            label_x, label_y = map(int, label.groups())
+            self.assertGreaterEqual(label_x, rect_x)
+            self.assertLessEqual(label_x, rect_x + rect_width)
+            self.assertLess(label_y, rect_y)
+
     def test_future_extensions_exist_only_as_source_comments(self) -> None:
         comments = "\n".join(re.findall(r"<!--(.*?)-->", self.html, flags=re.S))
         visible_source = re.sub(r"<!--.*?-->", "", self.html, flags=re.S)