fix(chv): _load_playwright 须返回 sync_playwright() 实例

返回函数本身则无 __enter__，真实启动路径从未跑通过（P2 假实现
掩盖；2026-11-08 构建 #8 驱动 live 抓到）。回归测试钉死该契约。

chv-guest/chv-browser.py

@@ -181,7 +181,10 @@ def truncate_a11y(node, max_nodes=MAX_A11Y_NODES,
 
 
 def _load_playwright():
-    """懒加载 playwright；缺失时报明错（不静默假装有浏览器）。"""
+    """懒加载 playwright；缺失时报明错（不静默假装有浏览器）。
+    返回 sync_playwright() 的上下文管理器实例（须调用，
+    不能只返回 sync_playwright 函数本身——函数没有 __enter__，
+    2026-11-08 构建 #8 驱动 live 抓到：真实路径从未跑通过）。"""
     os.environ.setdefault("PLAYWRIGHT_BROWSERS_PATH",
                           PLAYWRIGHT_BROWSERS_PATH)
     try:
@@ -190,7 +193,7 @@ def _load_playwright():
         raise RuntimeError(
             "chv-browser: playwright 未装（%s），浏览器子代理不可用"
             % e)
-    return sync_playwright
+    return sync_playwright()
 
 
 def _fetch_cdp_version(port, timeout=5.0):

cloud/tests/test_chv_opt_stage3.py

@@ -234,6 +234,28 @@ class ScreenshotTest(unittest.TestCase):
 
 
 class CdpAndStatusTest(unittest.TestCase):
+    def test_load_playwright_returns_context_manager(self):
+        # 2026-11-08 live 根因：_load_playwright 返回 sync_playwright
+        # 函数本身（无 __enter__），真实启动路径从未跑通过。
+        import sys
+        import types
+
+        class FakeCM:
+            def __enter__(self):
+                return self
+
+            def __exit__(self, *exc):
+                return False
+
+        fake_mod = types.ModuleType("playwright.sync_api")
+        fake_mod.sync_playwright = lambda: FakeCM()
+        with mock.patch.dict(sys.modules,
+                             {"playwright.sync_api": fake_mod}):
+            cm = BROWSER._load_playwright()
+        self.assertTrue(hasattr(cm, "__enter__"))
+        self.assertTrue(hasattr(cm, "__exit__"))
+        self.assertIsInstance(cm, FakeCM)
+
     def test_cdp_returns_websocket_url(self):
         with tempfile.TemporaryDirectory() as tmp:
             agent, _c, _h = _agent([FakePage()], tmp)