- Consolidate 9 TEST_CASEs into 1 SCENARIO with 11 SECTIONs - Add helper lambdas: propagate_n_periods, compute_energy, compute_period - Use named tolerance constants for all WithinAbs assertions - Tighten tolerances based on observed errors (REL_TOL 1e-9→1e-14) - Convert TOML to 1.0 inline table syntax - Add precalc script for expected values - Remove duplicate setup code across test cases Old test: 348 lines, 9 TEST_CASEs New test: 330 lines, 1 SCENARIO, 11 SECTIONs Net: -18 lines, -8 test cases