Create basic collision detection for base placement

Objective

Implement collision detection system to ensure bases and future buildings cannot overlap with terrain obstacles or each other.

Requirements

• Terrain Collision: Detect collisions with map obstacles
• Entity Collision: Prevent overlap between bases and buildings
• Footprint Validation: Check entire building footprint, not just center point
• Performance: Fast collision checking for real-time validation

Technical Details

• Implement spatial collision detection algorithms
• Create collision maps for efficient lookup
• Add bounding box collision for rectangular buildings
• Handle multi-tile entity footprints
• Optimize collision queries for performance
• Add visual feedback for valid/invalid placement

Acceptance Criteria

• Collision detection prevents invalid base placement
• System handles multi-tile building footprints
• Collision checking is performant for real-time use
• Visual feedback shows valid/invalid placement areas
• Edge cases (map boundaries) are handled correctly

Milestone Relation

Fundamental for MVP building placement. Required for base placement system and foundation for future building construction mechanics.