v0.5.1 - Documentation improvements

Add references and clickable links to all metrics in Methodology section:

- TF-IDF/Cosine Similarity: Salton & Buckley (1988)
- Redundancy Score: DRY principle, Hunt & Thomas (1999)
- Inheritance Violation: Liskov Substitution Principle
- Lateral Duplication: Roy & Cordy (2007) clone detection survey
- Compression Ratio: Benedetto et al. (2002)
- Distinct-N: Li et al. (2016) NAACL-HLT
- Instruction Density: RFC 2119
- Verb Density: Strunk & White (1959)
- Cross-File Vocabulary Overlap: Manning et al. (2008)
- Specificity Ratio: Spärck Jones (1972)
- Position Importance Score: Liu et al. (2023) arXiv:2307.03172
- Negative Constraint Ratio: Anthropic Claude's Character
- Hedging Density: Singhal et al. (2023) arXiv:2310.03716
- Boilerplate Lead Score: Xiao et al. (2024) arXiv:2309.17453

Updated dashboard screenshot.