Task 444: Sync TS and Rust Physics Constants

Status: DONE

Summary

Cross-language comparison found mismatches between TS (orbital.ts) and Rust (constants.rs):

1. MU.JUPITER: TS 1.26686534e8 vs Rust 1.266_865_349e8 (0.9 km³/s²)
2. MU.SATURN: TS 3.7931187e7 vs Rust 3.793_120_749e7 (20.49 km³/s²)
3. EARTH radius: TS 6_371 (mean) vs Rust 6_378.137 (equatorial)

Update TS to match the higher-precision Rust values (both sourced from JPL DE440/441).

Earth radius mismatch is a known difference (mean vs equatorial) — document it.