hypercross
b98e8d66af
Replace the old `QueryBuilder` and `ForEach` callback pattern with a more performant, zero-allocation `Select` API using `ref struct` iterators. This change also updates the singleton implementation to use dedicated entities per component type rather than a single reserved entity. - Replace `QueryBuilder`/`QueryDescriptor` with generic `Query<T1..T6>` - Replace `ForEach` callbacks with `world.Select<T1..T6>()` iterators - Replace `EntityIterator` with `WorldQueryExtensions` - Update singleton logic to allocate one entity per component type - Add `FindEntity<T>` and `FindEntities<T>` lookup methods