fix(HEL-233): 去掉系统管理按钮属性多余引号，恢复点击

五个无值 data-system-* 属性名后多写了引号，选择器匹配失败导致按钮完全无效。
toast 改为在未打开抽屉时也能挂载，并补源码与真实点击回归。

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: multica-agent <github@multica.ai>

tests/test_mobile_system_pages.py

@@ -57,3 +57,22 @@ class MobileSystemPagesRegressionTests(unittest.TestCase):
             'location.assign("/login/")',
         ):
             self.assertIn(marker, pages)
+
+    def test_system_boolean_attrs_do_not_have_stray_quotes(self) -> None:
+        pages = PAGES.read_text(encoding="utf-8")
+        stray = re.findall(r'data-system-[a-z-]*"(?=[>\s])', pages)
+        self.assertEqual(
+            stray,
+            [],
+            "boolean data-system attributes must not have a trailing quote before > or space",
+        )
+        for name in (
+            "data-system-save-birth",
+            "data-system-save-password",
+            "data-system-add-model",
+            "data-system-save-models",
+            "data-system-save-market",
+            "data-system-refresh",
+        ):
+            self.assertIn(name, pages)
+            self.assertNotIn(name + '">', pages)