Physics MCP Server

Initializes a new rigid-body physics world with configurable gravity and
timestep. Returns a simulation ID used for all subsequent operations.

Args:
    gravity_x: X component of gravity vector (m/s²). Default 0.0
    gravity_y: Y component of gravity vector (m/s²). Default -9.81 (Earth down)
    gravity_z: Z component of gravity vector (m/s²). Default 0.0
    dimensions: 2 or 3 for 2D/3D simulation. Default 3.
    dt: Simulation timestep in seconds. Default 0.016 (60 FPS).
        Smaller = more accurate but slower, larger = faster but less stable
    integrator: Integration method. Options: "euler", "verlet", "rk4". Default "verlet".

Returns:
    SimulationCreateResponse containing:
        - sim_id: Unique simulation identifier (use for all other sim calls)
        - config: Echo of the configuration used

Tips for LLMs:
    - Keep simulation IDs in memory for the conversation session
    - Default gravity is Earth standard (9.81 m/s² down = -Y direction)
    - dt=0.016 ≈ 60 FPS, dt=0.008 ≈ 120 FPS (higher accuracy)
    - "verlet" integrator is good default (stable, energy-conserving)
    - Remember to destroy_simulation when done to free resources

Requires:
    - Rapier provider must be configured (see config.py)
    - Rapier service must be running (see RAPIER_SERVICE.md)

Example:
    # Create simulation with Earth gravity
    sim = await create_simulation(
        gravity_y=-9.81,
        dt=0.016
    )
    # Use sim.sim_id for add_body, step_simulation, etc.