Consolidate 9 TEST_CASEs into 5 SCENARIOs with 22 SECTIONs:
- Load orbital parameters from TOML config instead of hardcoded constants
- Use precomputed expected values via precalc_analytical_propagation.py
- Apply tight tolerance constants (REL_TOL, ANG_TOL, R_TOL, V_TOL)
- Remove decorative comment blocks and redundant SCENARIO title comments
- Fix propagate_orbital_elements/orbital_elements_to_cartesian API usage
(both take parent_mass, not mu)
- Add destroy_simulation cleanup to each SCENARIO
New files: precalc_analytical_propagation.py, test_analytical_propagation.toml