⚡ Optimize StockService to fix N+1 queries using batch processing

[ManupaKDU]

💡 What: Refactored addItemNamesToAllStocks in StockService.java to use the batch processing approach provided by AbstractFacade (batchEdit) outside the main for loop instead of individually calling edit(s) inside the loop.
🎯 Why: Calling an EJB database operation like edit directly inside a loop that iterates over a large dataset (allStocks) results in severe N+1 performance degradation and potential transaction congestion. Executing database calls in bulk is a core optimization practice for JPA applications.
📊 Measured Improvement: While a fully automated benchmark for EJB facades cannot be executed outside of an application container within this particular standard test framework (and due to the absence of mocking frameworks like Mockito), the theoretical performance difference is significant. A loop of 1,000 entities shifts from making 1,000 separate database transaction operations (O(N) operations) to a single sequence of batched updates executed in sets of 25 (O(N/batchSize) database interactions). This results in far fewer context switches, round trips, and lock acquisitions in the persistence layer.

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PR created automatically by Jules for task 15603709256168628465 started by @manupawickramasinghe

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