feat(sp32): extract 837p NM1*82 (rendering provider NPI) per ClaimOutput

backend/tests/test_parse_837.py

@@ -68,3 +68,16 @@ def test_parse_uses_generic_config_when_requested():
     assert len(result.claims) == 1
     # No patient-loop rule on generic config
     assert result.claims[0].validation.passed is True
+
+
+def test_parse_837_extracts_rendering_provider_npi_from_nm1_82():
+    """SP32: NM1*82 (rendering provider) populates ClaimOutput.rendering_provider_npi."""
+    from pathlib import Path
+
+    text = Path("tests/fixtures/co_medicaid_837p_with_renderer.txt").read_text()
+    result = parse(text, PayerConfig.co_medicaid())
+    assert len(result.claims) >= 1
+    # Find the claim that has the rendering NPI (others may not).
+    matches = [c for c in result.claims if c.rendering_provider_npi is not None]
+    assert len(matches) == 1
+    assert matches[0].rendering_provider_npi == "1234567893"