`get_calls` iterated `generate_symbols` and overwrote `call.api` with
each generated symbol name, then yielded a `CallHandle` wrapping the
same `call` object. Because the Pydantic model is shared by reference,
every previously-yielded handle ended up with `api` equal to the last
symbol generated in the final iteration.
The correct pattern (used in `call.py:61`) is to leave the model
untouched and let the call extractor expand symbol variants via
`generate_symbols`. `get_calls` now yields exactly one `CallHandle`
per call with the original `api` value preserved.
