⚡ Bolt: Optimize LINQ Dictionary Allocations in NetworkSimulationEngine

[google-labs-jules]

💡 What: Replaced several expensive LINQ operation chains (like GroupBy().ToDictionary(), .Select().ToDictionary()) with explicit foreach loops and pre-sized collections inside NetworkSimulationEngine.cs.
🎯 Why: In C#, LINQ methods on hot paths cause significant memory allocations via enumerators, delegates, and closures. By converting these to manual pre-sized loops, we drastically cut down on garbage collection pressure and CPU overhead during network compilation phases.
📊 Impact: Eliminates $O(N)$ and $O(T)$ (Traffic Types) hidden enumerator allocations inside the simulation start sequence, yielding faster simulation initialization times, particularly for complex scenarios.
🔬 Measurement: Verify changes by tracking reduced memory allocation metrics in a profiler when triggering simulations. Run the full xUnit test suite (dotnet test) to ensure accurate calculation routing is preserved.

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PR created automatically by Jules for task 17250435971318481167 started by @wnj00524

[google-labs-jules]

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