Feature suggestion: Animated filter option

At some point during designing filter options (#113), I remember talking about having a checkbox next to "Downloadable" entities for "Animated" entities. Now that the `AnimationController` is in testing, it might make sense to think about this again?

## Implementation Suggestion

The `@gltf-transform` packages allow reading `glTF` and `glb` files to read their scene graph. This also allows reading their animation list. We could use this identify uploaded files which contain animations.

Since [Kompakkt/Kompressor](https://github.com/Kompakkt/Kompressor) already has this package installed, it would be an option to add it there.

The server would need to check all uploaded entities for animations, but this can be done in the background, to save on processing power (or more accurately, run a job which asks Kompressor if a 3D model has animations).

@Grizzly127 @ZetOE do you think this would be a nice addition?

Example code used for testing

```typescript
import { Document, NodeIO } from "@gltf-transform/core";
import { ALL_EXTENSIONS } from "@gltf-transform/extensions";
import draco3d from "draco3dgltf";

const io = new NodeIO().registerExtensions(ALL_EXTENSIONS).registerDependencies({
"draco3d.decoder": await draco3d.createDecoderModule(), // Optional.
"draco3d.encoder": await draco3d.createEncoderModule(), // Optional.
});

// Read from URL.
const document = await io.readBinary(
await Bun.file("/home/kai/Models/B005_KleinesTheater_A_2K_v03.glb").bytes(),
);

console.log(document.getRoot().listAnimations().at(0));
```

Start by reviewing the filter work in #113 and the current AnimationController testing. Then inspect how Kompakkt/Kompressor handles uploaded entities and how the frontend represents the "Downloadable" filter. Done means animated uploads can be identified through the glTF transform packages and exposed through an "Animated" filter, with background processing accounted for.

Written by the indexing model from the issue text.