refactor: test_hybrid_burns - impulse + continuous burn behavior
- 14 TEST_CASEs consolidated into 1 SCENARIO with 22 SECTIONs
- Shared fixture: sim, bodies, all spacecraft, maneuvers
- Helper lambdas: init_craft, find_maneuver, exec_by_name
- All tolerances precalculated via sim_engine.py
- Named tolerance constants (A_TOL, E_TOL, V_TOL)
- 112 assertions, all passing
- Updated continue.md: no decorative comments, REQUIRE for integers