Srkuls's Custom Shields

# 🚀 Initial Release - v1.0.0

Welcome to the initial release of **Srkul's Custom Shields**!

### ✨ What's New:
- **5 Custom Shield Subpacks**: Added 5 unique shield variants accessible via in-game pack settings:
  - Default Minecraft Shield (Vanilla)
  - Golden Geometric Shield
  - Royal Lion Shield
  - Creeper Wooden Shield
  - Cosmic Lightning Shield
- **Custom Back & Rim Textures**: Added detailed oak wood textures for the back of the shield and metallic trims.
- **In-Game Settings Slider**: Seamless variant switching without replacing pack files.
- **Minecraft 1.20+ Support**: Fully tested and compatible with Minecraft Bedrock & Java resource configurations.