Add entity clone, component remove and reparent commands

[waynemwashuma]

Objective

Introduces additional high-level entity commands for cloning entities, removing components, and reparenting entities while preserving their world transforms.

Solution

The new operations are implemented as dedicated commands and queued through the existing EntityCommands API.

Changes Made

• Introduce EntityCommands.clone() creates a hierarchy-aware clone by traversing the source entity's descendants, cloning registered components and remapping entity relationships to the cloned hierarchy.
• Introduce EntityCommands.reparent() recalculates an entity's local transform relative to its new parent before changing the Parent component. It handles both 2D and 3D transforms and prevents an entity from being reparented to itself or one of its descendants..
• Introduce EntityCommands.remove() for removing a tuple of components from an entity.

Why This Approach

• Entity mutations remain deferred through the existing command queue.
• Cloning the hierarchy as a group allows parent-child relationships to be reconstructed using the cloned entity IDs.
• Using TypeRegistry keeps component cloning extensible and avoids requiring individual component types to be handled explicitly.
• Reparenting through inverse parent transforms preserves the entity's world-space transform while changing its local transform.
• Dedicated commands keep the operations isolated and allow them to participate in the existing command execution pipeline.

Showcase

Before

Entities could be spawned and despawned through EntityCommands, but there was no command-level API for cloning, removing components or reparenting.

After

Entities can now be easily cloned, have components removed and be reparented:

const commands = new EntityCommands(world)

const clone = commands.clone(entity)

commands.remove(entity, [ComponentA, ComponentB])

commands.reparent(entity, parent)

Migration Guide

No migration required.

Checklist

• I have updated the documentation accordingly.
• I have added tests to cover my changes.