Support the iTwin RealityData type Gaussian Splat OGC 3D Tiles

[alarkbentley]

Description

Add support for RealityData of type Gaussian Splat OGC 3D Tiles (GS_3DT) to ITwinData.createTilesetForRealityDataId.
See: https://developer.bentley.com/apis/reality-management/rm-rd-details/#types

Example

// Create tileset of the reality data mesh of type GaussianSplat3DTiles
const realityMesh = await Cesium.ITwinData.createTilesetForRealityDataId({
  iTwinId,
  realityDataId,
  type: ITwinPlatform.RealityDataType.GaussianSplat3DTiles,
});
scene.primitives.add(realityMesh);

Demo

Example from iTwin: Catalog_GaussianSplats
https://connect-contextshare.bentley.com/itwins/6d99d26e-73fb-4ade-adac-9580d5ecf39f

Metadata:

{
    "realityData": {
        "id": "ed61052a-8337-43d7-8887-0c4ede19ad6c",
        "displayName": "Flex_GS_Topcon_Medium_3DT",
        "classification": "Model",
        "type": "GS_3DT",
        "description": "3D model created with iTwin Capture Modeler Flex",
        "tags": [],
        "rootDocument": "tileset.json",
        "dataCenterLocation": "East US",
        "authoring": false,
        "size": 44361,
        "acquisition": {
            "startDateTime": "2019-05-29T07:40:07Z",
            "endDateTime": "2019-05-29T09:46:06Z"
        },
        "accessControl": "ITwin",
        "modifiedDateTime": "2026-02-10T17:15:00Z",
        "lastAccessedDateTime": "2026-02-13T02:07:10Z",
        "createdDateTime": "2026-02-10T16:12:23Z",
        "ownerId": "2d8caa73-f93c-462b-aaf0-194c8ef2bacc"
    }
}

Author checklist

• I have submitted a Contributor License Agreement
• I have added my name to CONTRIBUTORS.md
• I have updated CHANGES.md with a short summary of my change
• I have added or updated unit tests to ensure consistent code coverage
• I have updated the inline documentation, and included code examples where relevant
• I have performed a self-review of my code

[github-actions]

Thank you for the pull request, @alarkbentley!

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