Fix body list format for raygui compatibility

- Convert body names array to semicolon-separated string format
- Fix GuiListView parameter usage with proper format
- Ensure proper memory management for body list text

src/renderer.cpp

@@ -376,12 +376,17 @@ void render_body_list_ui(SimulationState* sim, RenderState* render_state) {
 
     Rectangle panel_bounds = { (float)panel_x, (float)panel_y, (float)panel_width, (float)panel_height };
 
-    // Create body list for raygui
-    const char** body_names = (const char**)malloc(sim->body_count * sizeof(char*));
-    if (!body_names) return;
-
+    // Create body list string for raygui (NULL-terminated)
+    char* body_list_text = (char*)malloc(sim->body_count * 64); // 64 chars per name max
+    if (!body_list_text) return;
+    
+    body_list_text[0] = '\0'; // Initialize empty string
+    
     for (int i = 0; i < sim->body_count; i++) {
-        body_names[i] = sim->bodies[i].name;
+        if (i > 0) {
+            strcat(body_list_text, ";"); // Separator for raygui
+        }
+        strcat(body_list_text, sim->bodies[i].name);
     }
 
     // Draw window
@@ -397,21 +402,18 @@ void render_body_list_ui(SimulationState* sim, RenderState* render_state) {
         (float)panel_height - 29 
     };
     
-    int focus = 0;
-    int active = 0;
-    if (render_state->selected_body_index >= 0 && render_state->selected_body_index < sim->body_count) {
-        focus = render_state->selected_body_index; // 0-based indexing for scroll
-        active = 1; // Mark as active
-    }
+    int focus = render_state->selected_body_index; // 0-based indexing
+    if (focus < 0) focus = 0;
     
-    int result = GuiListView(list_bounds, (const char*)body_names, &focus, &active);
+    int active = 0; // Raygui uses this internally
+    int result = GuiListView(list_bounds, body_list_text, &focus, &active);
     
     if (result >= 0 && result < sim->body_count) {
         render_state->selected_body_index = result;
         render_state->show_body_info = true;
     }
 
-    free(body_names);
+    free(body_list_text);
 }
 
 // Render body information UI panel