🛡️ Sentinel: [CRITICAL] Fix SQL injection in StockController

[ManupaKDU]

🚨 Severity: CRITICAL
💡 Vulnerability: SQL Injection via string concatenation in JPQL queries in StockController.java.
🎯 Impact: Attackers could potentially execute unauthorized database queries or bypass security checks.
🔧 Fix: Replaced string concatenation with parameterized JPQL queries using HashMap parameters.
✅ Verification: Ran mvn clean test to ensure tests passed. Code manually reviewed to verify parameterization correctly handles strings.

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PR created automatically by Jules for task 4594918607480862428 started by @manupawickramasinghe

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