- Introduced a new body type "simple_box" with defined mass and added mass matrices in `simple_box.json`.
- Created scenarios for bodies with initial velocity and two bodies at rest in `body_with_initial_velocity.json` and `two_bodies_at_rest.json`, respectively.
- Implemented tests in `TestScenarioReader.cpp` to validate parsing of scenarios, body types, and simulation behavior.
- Ensured that bodies at rest remain at rest after simulation steps and that initial conditions are correctly applied.