Interactive, single node box_shadow example

- Replaces the previous static example with a single, central node with adjustable settings as per issue suggestion.
- Implements button-based setting adjustments. Slider widgets don't seem available yet.
- Improved overall aesthetics of the example
- Dynamically recolors shadows for visual clarity when increasing shadow count.
- Adjustable Settings:
    - Shape selection
    - Shadow X/Y offset, blur, spread, and count
- Added Reset button to restore default settings

Author: oracle58