Summary

Major changes:
Introduced CrystalToolkitAnimationScene to enable crystal structure animations. For each Object3D, the scene renders keyframes (position, scale, or quaternion ...) and performs linear interpolation between frames for smooth transitions.

• feature 1: Added the animateType field to interface SceneJsonObject in simple-scene.ts.
  This field can be either "position" or "displacement", specifying the physical interpretation of the animate data in each scene entry.

• feature 2: Support for generating multiple keyframes added to buildAnimationSupport in animation-helper.ts
  fix: Previously, the code only parsed the first two frames; this has now been corrected

• testing: The page /components/crystal-toolkit/pages/CrystalStructureAnimationViewer/CrystalStructureAnimationViewer.tsx is used for testing with sample data, along with the scene files /components/crystal-toolkit/scene/phonon-animation-scene.ts and /components/crystal-toolkit/scene/phonon-animation-position-scene.ts.

TODO:

• Currently supports animation for SPHERES and CYLINDERS (representing atoms and bonds). Animation for LINES (unit cell edges), CONVEX, and BEZIER geometries is not yet implemented.
• Added BooleanKeyframeTrack support for bond-breaking animations. Bonding is represented using two endpoints, typically derived from pymatgen.analysis.local_env.CrystalNN and pymatgen.analysis.graphs.StructureGraph. In cases where a bond breaks or reforms, the associated Object3D is toggled invisible to reflect the change visually.
• The function get_scene from StructureGraph and Site in crystal_toolkit.components.renderables is used to generate animation data for atoms and bonds. A separate PR will be submitted to crystal_toolkit(Retain atom index info in _meta crystaltoolkit#470)

Checklist

• - Performance testing (Browser)

Local Testing

Run npm start and navigate to http://localhost:1234/crystal_animation