⚡ Bolt: [performance improvement] Add React.memo to ProductCard

[Dev22603]

💡 What: Wrapped ProductCard component export in React.memo().
🎯 Why: In lists of products (like on the Home page), ProductCard re-renders unnecessarily whenever the parent component updates unrelated state (like search queries or pagination).
📊 Impact: Reduces unnecessary re-renders of the product list. The list is long, so avoiding these re-renders saves DOM reconciliation operations.
🔬 Measurement: Use React Developer Tools Profiler to observe component rendering times during interactions like typing in the search bar or changing pages. ProductCard instances will only re-render if the product prop changes or context (like CartContext updates) changes.

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PR created automatically by Jules for task 9045413021449004022 started by @Dev22603

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