⚡ Bolt: Eliminate N+1 query bottlenecks in manual lending and history views

[Woschj]

💡 What: Optimized four key service methods in LendingService (get_active_lendings, get_recent_consumable_usage, get_worker_consumable_history, get_tool_lending_history) to use single MongoDB aggregation pipelines with $lookup instead of loop-based find_one calls. Refactored the manual_lending route to leverage these optimized services.

🎯 Why: The application was performing O(N) database queries when loading list views (e.g., fetching 100 lendings required 201 database round-trips).

📊 Impact: Reduces database round-trips from O(N) to O(1) for these common views. Benchmark tests showed query count reduction from 201 to 1 for a 100-item lending list.

🔬 Measurement: Verified with a custom benchmark script using mongomock that counts database calls before and after the optimization.

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PR created automatically by Jules for task 7153341987007641678 started by @Woschj

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