Remove old SeString class - #134

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/upload-artifact@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Non-nullable property 'Materials' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Non-nullable property 'Meshes' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Dereference of a possibly null reference.

Non-nullable field 'Bones' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Dereference of a possibly null reference.

'NodeData.NineGridNode.Unk1' is obsolete: 'Renamed to BlendMode'

'NodeData.NumericInputComponentNode.Unk1' is obsolete: 'Renamed to EndLetterId'

Dereference of a possibly null reference.

Dereference of a possibly null reference.