`def read_body(response: httpx.Response)` names an external type, but a private
`class _Response` in a test file absorbed the reference, producing a fabricated
EXTRACTED-confidence edge from production code to test code.
The stub-rewire key (`_node_label_key`) stripped ALL non-alphanumeric
characters, including underscores, so `_Response` and `Response` collapsed to
the same key and the lone local `_Response` was chosen as the unique match.
Underscores are significant identifier characters, so the key now preserves
them (only `()`, `<>`, `.`, and whitespace are dropped); `Foo()` still matches
`Foo`, but `_Response` no longer matches `Response`.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
