fix(s52): scrub every URL-bearing exception path in WebhookNotifier

tests/test_notify.py

@@ -108,7 +108,8 @@ def test_webhook_posts_correct_payload() -> None:
 
 def test_webhook_default_post_is_urllib_post() -> None:
     """inspect.signature proves the stdlib default WITHOUT opening a socket — ``_urllib_post`` is
-    the single socket path and is never called by the offline suite."""
+    the single socket path; the offline suite never lets it reach a socket (the only in-suite
+    call uses a scheme-less URL that fails at parse time)."""
     sig = inspect.signature(WebhookNotifier.__init__)
     assert sig.parameters["post"].default is _urllib_post