test(py-lsp): regression for #228 (cross-file classmethod on class)

#228: a class/static method invoked on a cross-file imported class name
(ActionRecordX.build_from_text(...)) produced no CALLS edge, so the
method looked like dead code (in/out degree 0). The v0.7.0 py_lsp
cross-file resolver handles this; the test feeds the exact pattern through
cbm_run_py_lsp_cross and asserts the call resolves.

Closes #228.