[feat] Add Strandbeests to Paddock

[hasjack]

Strandbeest Integration

Implement Theo Jansen's Strandbeests in the Paddock, creating a space where digital horses and mechanical creatures can coexist and interact. This project combines artistic vision with technical innovation, bringing wind-powered mechanical life to our digital beach.

Core Components

1. Physics & Movement

   • Implement Jansen linkage system with exact ratios
   • Create wind-powered movement mechanics
   • Add collision detection for legs

2. Beach Environment

   • Add beach biome at paddock edge
   • Implement sand particle system
   • Create wave and shoreline effects

3. Integration

   • Extend PaddockCollision for sand physics
   • Add BiomeManager for beach zone
   • Implement WindSystem for force calculations

4. Interaction

   • Enable horse-beest interactions
   • Create footprint system in sand
   • Add wind sharing mechanics

Technical Foundation

• See full spec in specs/strandbeest-integration.md
• Uses Theo Jansen's sacred ratios for authentic movement
• Builds on existing Paddock physics system
• Preserves artistic vision while adding technical innovation

Success Criteria

• Strandbeests move naturally with wind
• Horses can interact with beests
• Beach environment feels alive
• Performance remains smooth
• Honors Theo's original vision

[hasjack]

Created sub-issue #66 for implementing the beach biome component with sand physics and wave mechanics. This will be a critical part of the Strandbeest habitat.