Inspector v2: Picking toolbar

[ryantrem]

This PR adds a picking button to the toolbar for picking objects from the scene.

The picking logic is similar to inspector v1, but fixes a handful of bugs as well.

• Picking gizmos doesn't work in v1, at least not in any way I expect it to as a user or looking at the existing code. It works in v2.
• Picking meshes with morph target or skeletal animations does not work in v1. It works in v2.

The picking logic also uses the "Ignore Backfaces for Picking" setting that @deltakosh already added to the settings pane.

Other changes:

• Fixed a bug that was introduced 5 years ago where the isHovered state on a gizmo is only updated on pointer click, not on pointer move, which means if you click on it, it just stays in the "hovered" state indefinitely.

[bjsplat]

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[bjsplat]

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[bjsplat]

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[bjsplat]

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[bjsplat]

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[bjsplat]

Visualization tests for WebGPU

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