ICON REGISTRY NOTES

File:
- custom_calendar_package/ui/icon_registry.json

Each entry can point to:
- emoji
- text
- svg
- image
- spritesheet
- sprite_x
- sprite_y
- sprite_w
- sprite_h

Intended use:
- terms: generic UI symbols like Home Sign or Zodiac Age
- bodies: planets, moons, stars, dwarves
- signs: zodiac signs

If an asset is null or missing, the UI falls back to text / emoji / built-in glyphs.
