🧪 test: add unit tests for QuadTree duplicate position insertions

[johnstrand]

🎯 What: Added tests covering QuadTree insertion behavior for duplicate positions and edge cases around capacity/depth limits.
📊 Coverage:

• Inserting many items at exact duplicate positions up to and past node capacity without infinite loops.
• Querying (both AABB and radius queries) and removing duplicate items at identical positions.
• Exceeding node capacity and max depth bounds.
  ✨ Result: Enhanced test coverage and reliability for QuadTree spatial partitioning edge cases.

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PR created automatically by Jules for task 17529069066832394352 started by @johnstrand

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