Refactor: BoundingSphereDebug optimization + javadoc

[capdevon]

These changes result in a cleaner, more robust, and easier-to-understand BoundingSphereDebug implementation.

• Refactored the BoundingSphereDebug class for improved clarity and maintainability.
• Simplified geometry generation for the bounding sphere debug mesh.
• Added explicit generation and coloring of three axis-aligned circles (XY: blue, XZ: green, YZ: yellow) to visually represent the bounding sphere.
• Introduced a helper method to handle circle vertex and color data creation.
• Improved documentation and code comments for better understanding.
• Implemented serialization support by adding write() and read() methods for the radialSamples property.
• Updated copyright year in the file header.
• Removed unused or redundant class fields and code.