Add massive neutrino support and improve CSV/CLI output

- Add neutrino mass parameter to SpectrumConfig and CLI interface
- Update PhaseSpace component to handle neutrino mass effects properly
- Update CSV headers to show basic endpoint and all transition types
- Add --csv-verbosity option to CLI with 'full' and 'concise' options
- Fix comparison plots to properly show linear scale variations
- Add comprehensive tests for neutrino mass functionality

beta_spectrum/cli.py

@@ -85,6 +85,12 @@ def _build_parser() -> argparse.ArgumentParser:
         default=0.001,
         help="Energy step size in MeV (default: 0.001). All energies are in MeV throughout the toolkit.",
     )
+    parser.add_argument(
+        "--neutrino-mass",
+        type=float,
+        default=0.0,
+        help="Neutrino mass in MeV (default: 0.0). Set to non-zero value to include neutrino mass effects in phase space calculation.",
+    )
 
     # Output
     parser.add_argument(
@@ -139,6 +145,13 @@ def _build_parser() -> argparse.ArgumentParser:
         "(default: 0.0 = include all branches). "
         "Branches below this threshold are excluded from the calculation and plots.",
     )
+    log_group.add_argument(
+        "--csv-verbosity",
+        type=str,
+        default="full",
+        choices=["full", "concise"],
+        help="CSV output verbosity: 'full' (all components) or 'concise' (total spectrum and normalized branch components only) (default: full)",
+    )
 
     return parser
 
@@ -237,6 +250,7 @@ def _run(args: argparse.Namespace) -> None:
                     endpoint_MeV=decay_info.endpoint_MeV,
                     transition_type=decay_info.transition_type,
                     e_step_MeV=args.e_step,
+                    neutrino_mass_MeV=args.neutrino_mass,
                     branches=branches,
                     intensity_cutoff=args.intensity_cutoff,
                 )
@@ -246,6 +260,7 @@ def _run(args: argparse.Namespace) -> None:
                     nuclide=source_value,
                     e_step_MeV=args.e_step,
                     intensity_cutoff=args.intensity_cutoff,
+                    neutrino_mass_MeV=args.neutrino_mass,
                 )
         else:
             config = create_config_from_source(
@@ -253,6 +268,7 @@ def _run(args: argparse.Namespace) -> None:
                 nuclide=source_value,
                 e_step_MeV=args.e_step,
                 intensity_cutoff=args.intensity_cutoff,
+                neutrino_mass_MeV=args.neutrino_mass,
             )
     else:
         logger.info("Source: JSON file=%s", source_value)
@@ -288,7 +304,9 @@ def _run(args: argparse.Namespace) -> None:
     # Export to CSV
     if args.output:
         analyzer = BetaSpectrumAnalyzer(spectrum, config, logger=logger)
-        analyzer.export_to_csv(args.output, source_type=source_type)
+        analyzer.export_to_csv(
+            args.output, source_type=source_type, csv_verbosity=args.csv_verbosity
+        )
         logger.info("Spectrum exported to %s", args.output)
 
     # Generate plot
@@ -333,6 +351,7 @@ def _print_dry_run_output(config, source_type: str) -> None:
     print(f"Endpoint:   {config.endpoint_MeV * 1000:.1f} keV")
     print(f"Transition: {config.transition_type}")
     print(f"e_step:     {config.e_step_MeV:.4f} MeV")
+    print(f"neutrino_mass_MeV: {config.neutrino_mass_MeV:.6f}")
     print(f"Corrections: {', '.join(enabled) if enabled else 'none'}")
 
     if config.branches and len(config.branches) > 1: