refactor(cli): delegate paceENSDF config building to library

Remove the duplicated inline paceENSDF config builder in the CLI.
It renormalized branch intensities before filtering, diverging from
the library decay_info_to_config path that library callers use
(audit finding D5). CLI paceENSDF configs now come from
create_config_from_source exactly once per run.

Regression test spies on create_config_from_source during a CLI run.

beta_spectrum/cli.py

@@ -178,15 +178,10 @@ def _run(args: argparse.Namespace) -> None:
     from beta_spectrum.logging_utils import get_logger
     from beta_spectrum.nuclear_data import (
         create_config_from_source,
-        get_decay_info_from_paceENSDF,
         json_to_config,
         load_json_input,
     )
-    from beta_spectrum.spectrum import (
+    from beta_spectrum.spectrum import BetaSpectrum
-        BetaSpectrum,
-        BranchConfig,
-        SpectrumConfig,
-    )
     from beta_spectrum.output import BetaSpectrumAnalyzer
 
     # Determine logging level
@@ -246,53 +241,10 @@ def _run(args: argparse.Namespace) -> None:
     csv_separator = "," if args.csv_separator is None else args.csv_separator
     normalize_to_one = bool(args.normalize_to_one)
 
-    # Build config
+    # Build config — a single delegated path for every data source.
     config: SpectrumConfig
     if source_type == "paceENSDF":
         logger.info("Source: paceENSDF nuclide=%s", source_value)
-        decay_info = get_decay_info_from_paceENSDF(source_value, "beta_minus")
-
-        # Normalize branch intensities to sum to 1.0
-        if decay_info.branches:
-            total_intensity = sum(b.intensity for b in decay_info.branches)
-            if total_intensity > 0:
-                branches = [
-                    BranchConfig(
-                        endpoint_MeV=(
-                            (decay_info.endpoint_MeV - b.level_energy_keV / 1000.0)
-                            if b.level_energy_keV > 0
-                            else decay_info.endpoint_MeV
-                        ),
-                        transition_type=b.transition_type,
-                        intensity=b.intensity / total_intensity,
-                    )
-                    for b in decay_info.branches
-                    if b.intensity / total_intensity >= intensity_cutoff
-                ]
-                config = SpectrumConfig(
-                    Z_parent=decay_info.Z_parent,
-                    Z_daughter=decay_info.Z_daughter,
-                    A_number=decay_info.A_number,
-                    endpoint_MeV=decay_info.endpoint_MeV,
-                    transition_type=decay_info.transition_type,
-                    e_step_MeV=e_step_MeV,
-                    neutrino_mass_MeV=neutrino_mass_MeV,
-                    branches=branches,
-                    intensity_cutoff=intensity_cutoff,
-                    csv_separator=csv_separator,
-                    normalize_to_one=normalize_to_one,
-                )
-            else:
-                config = create_config_from_source(
-                    "paceENSDF",
-                    nuclide=source_value,
-                    e_step_MeV=e_step_MeV,
-                    intensity_cutoff=intensity_cutoff,
-                    neutrino_mass_MeV=neutrino_mass_MeV,
-                    csv_separator=csv_separator,
-                    normalize_to_one=normalize_to_one,
-                )
-        else:
         config = create_config_from_source(
             "paceENSDF",
             nuclide=source_value,

tests/integration/test_cli_flows.py

@@ -162,3 +162,30 @@ class TestCLIPaceENSDF:
             main(["Tc99", "--output", out, "--neutrino-mass", "0.35"])
         assert exc.value.code == 1
         assert not (tmp_path / "tc99deg.csv").exists()
+
+    def test_cli_builds_paceensdf_config_via_library(
+        self, monkeypatch: Any, capsys: Any
+    ) -> None:
+        """CLI must delegate paceENSDF config building to the library
+        (create_config_from_source), not duplicate it inline (D5)."""
+        import beta_spectrum.nuclear_data as nuclear_data
+
+        real_builder = nuclear_data.create_config_from_source
+        calls: List[Dict[str, Any]] = []
+
+        def spy(source: str, **kwargs: Any) -> Any:
+            calls.append({"source": source, **kwargs})
+            return real_builder(source, **kwargs)
+
+        monkeypatch.setattr(nuclear_data, "create_config_from_source", spy)
+
+        main(["Cs137", "--dry-run", "--intensity-cutoff", "0.9"])
+        capsys.readouterr()
+
+        assert len(calls) == 1, (
+            "CLI must delegate paceENSDF config building to the library "
+            "builder exactly once"
+        )
+        assert calls[0]["source"] == "paceENSDF"
+        assert calls[0]["nuclide"] == "Cs137"
+        assert calls[0]["intensity_cutoff"] == 0.9