Fix/#2722 preload

[kvvasuu]

Why

Resolves #2722

<Preload /> has no visible effect — the scene loads and renders normally, but shader compilation stutter still occurs when the camera points at a new object for the first time.

What

⚠️ This implementation requires three.js r184 or later.

Updated the existing Preload component.

• Replaced gl.compile() with renderer.compileAsync()- works on both WebGLRenderer and WebGPURenderer
• Sets frustumCulled = false on all objects before compilation so off-screen objects are included
• Adds an onDone callback that fires after compilation completes and state is restored

Checklist

• Documentation updated
• Ready to be merged

[vercel]

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