Remove unused add_body() and consolidate velocity initialization

- Removed add_body() function (unused across codebase)
- Renamed compute_initial_velocities() to calculate_initial_velocities()
- Removed redundant wrapper function

Removed 26 lines of dead code

src/simulation.cpp

@@ -25,32 +25,6 @@ void destroy_simulation(SimulationState* sim) {
     }
 }
 
-// Add a celestial body to the simulation
-void add_body(SimulationState* sim, const char* name, double mass, double radius,
-              Vec3 pos, Vec3 vel, int parent_index, float r, float g, float b,
-              double eccentricity, double semi_major_axis) {
-    if (sim->body_count >= sim->max_bodies) {
-        return;  // No more space
-    }
-
-    CelestialBody* body = &sim->bodies[sim->body_count];
-    strncpy(body->name, name, 63);
-    body->name[63] = '\0';
-    body->mass = mass;
-    body->radius = radius;
-    body->position = pos;
-    body->velocity = vel;
-    body->soi_radius = 0.0;  // Will be calculated later
-    body->parent_index = parent_index;
-    body->color[0] = r;
-    body->color[1] = g;
-    body->color[2] = b;
-    body->eccentricity = eccentricity;
-    body->semi_major_axis = semi_major_axis;
-
-    sim->body_count++;
-}
-
 // Find which body is gravitationally dominant for the given body
 int find_dominant_body(SimulationState* sim, int body_index) {
     if (body_index < 0 || body_index >= sim->body_count) {
@@ -268,7 +242,7 @@ static void print_system_info_if_multiple_roots(int root_count, Vec3 barycenter)
     }
 }
 
-void compute_initial_velocities(SimulationState* sim) {
+void calculate_initial_velocities(SimulationState* sim) {
     int root_indices[32];
     int root_count;
     Vec3 barycenter = compute_system_barycenter(sim, root_indices, &root_count);
@@ -285,10 +259,6 @@ void compute_initial_velocities(SimulationState* sim) {
     set_child_bodies_velocity(sim);
 }
 
-void calculate_initial_velocities(SimulationState* sim) {
-    compute_initial_velocities(sim);
-}
-
 // Calculate SOI radii for all bodies
 void calculate_soi_radii(SimulationState* sim) {
     for (int i = 0; i < sim->body_count; i++) {

src/simulation.h

@@ -29,9 +29,6 @@ struct SimulationState {
 // Simulation management functions
 SimulationState* create_simulation(int max_bodies, double time_step);
 void destroy_simulation(SimulationState* sim);
-void add_body(SimulationState* sim, const char* name, double mass, double radius,
-              Vec3 pos, Vec3 vel, int parent_index, float r, float g, float b,
-              double eccentricity, double semi_major_axis);
 
 // SOI and simulation update functions
 int find_dominant_body(SimulationState* sim, int body_index);
@@ -39,7 +36,6 @@ void update_soi(CelestialBody* body, CelestialBody* parent, double semi_major_ax
 void update_simulation(SimulationState* sim);
 
 // Velocity initialization
-void compute_initial_velocities(SimulationState* sim);
 void calculate_initial_velocities(SimulationState* sim);
 
 // SOI helpers