replace per-tick allocations in push_text with an arena/bump allocator

apps/scenery/scenes/title.c

@@ -37,13 +37,8 @@ static void title_tick(State *state) {
         },
         (Color) { 0, 0, 0, 255 }
     );
-    push_text(
-        text_str,
-        (Vec2){ 0, 0 },
-        text_h,
-        (Color) { 255, 255, 255, 255 },
-        font
-    );
+    push_text(text_str, (Vec2){ 0, 0 }, text_h, (Color) { 255, 255, 255, 255 }, font);
+
     free(text_str);
 }