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

.llm-wiki/wiki/sources/SRC-2026-05-27-005.md

@@ -0,0 +1,41 @@
+---
+type: source
+format: web
+source_id: SRC-2026-05-27-005
+raw_path: raw/sources/SRC-2026-05-27-005/extracted.md
+captured: 2026-05-27
+status: skeleton
+---
+
+# https://arxiv.org/pdf/2506.17544
+> _Original: [https://arxiv.org/pdf/2506.17544](https://arxiv.org/pdf/2506.17544)_
+
+## Summary
+
+[LLM: Replace with 2-3 paragraph summary of key content]
+
+> _Auto-preview: 5202 nuJ 12 ]xe-lcun[ 1v44571.6052:viXra The measurement of the 99Tc β-decay spectrum and its implications for the effective value of weak axial coupling J. W. Song,1,2 M. Ramalho,3,4 M. K. Lee,1 G. B. Kim,5 I. Kim,5 H. L. Kim,6 Y. C. Lee,6,7 K. R. Woo,6 J. Kotila,8 J. Kostensalo,9 J. Suhonen,4,10,∗ and H. J. Kim2,† 1Korea Research Institute of Standards and Science, Daejeon 34113, South Korea 2Department of Physics, Kyungpook National University, Daegu 41566, South Korea 3School of Physics, Eng..._
+
+## Key Takeaways
+
+- [LLM: Most important point]
+- [LLM: Second important point]
+- [LLM: Third important point]
+
+## Entities Mentioned
+
+- [[entity-name]]
+
+## Concepts Mentioned
+
+- [[concept-name]]
+
+## Notable Quotes
+
+> [LLM: Important quote] — attribution
+
+## Source Packet
+
+- **ID:** `[[sources/SRC-2026-05-27-005]]`
+- **Extracted:** [raw/sources/SRC-2026-05-27-005/extracted.md](../raw/sources/SRC-2026-05-27-005/extracted.md)
+- **Manifest:** [raw/sources/SRC-2026-05-27-005/manifest.json](../raw/sources/SRC-2026-05-27-005/manifest.json)