Task 496: 3D Orbital Analysis JSON → Report Cross-Checks

Status: DONE

Added cross-checks validating that 3d_orbital_analysis.json values are properly cited in the cross-episode summary report.

Added 3d_orbital_analysis.json → report cross-checks describe block to article-content-validation.test.ts
13 new tests covering:

- Max plane change fraction (1.51%)

- Per-leg plane change ΔV (39.8, 0.4, 168.6, 82.6 km/s) and fraction % (0.47, 1.05, 1.51, 0.70)

- Saturn ring approach angle from Jupiter (~9.3°)

- Uranus approach angle from Saturn (~25.3°)

- Enceladus outside rings confirmation

Catches drift between 3D orbital analysis calculations and cross-episode report prose
Validates all 4 transfer legs' plane change values are accurately cited
Extends the analysis-derived cross-check pattern to another calculation JSON file