Switch to SOG format for splats

[willeastcott]

No description provided.

[Copilot]

Pull Request Overview

This PR switches the project from using PLY format to SOG format for Gaussian splat assets, updating the asset type mapping and example files to use the new format.

• Adds support for .sog file extension as a gsplat asset type
• Updates example HTML files to reference .sog files instead of compressed .ply files
• Adjusts rotation values in one example to accommodate the format change

Reviewed Changes

Copilot reviewed 3 out of 7 changed files in this pull request and generated no comments.

File	Description
src/asset.ts	Adds .sog extension mapping to gsplat type
examples/video-recorder.html	Updates biker splat asset from .ply to .sog format
examples/splat.html	Updates angel splat asset from .ply to .sog format and adjusts rotation

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