Initialise UI context

src/compositor.c

@@ -42,6 +42,9 @@ i32 run_main_loop(void) {
   }
 
   compositor_t comp = {0};
+
+  init_ui_ctx(&(comp.ctx));
+
   comp.rects = (rect_t *)malloc(sizeof(rect_t) * MAX_NODES);
   comp.nodes = (node_t *)malloc(sizeof(node_t) * MAX_NODES);