⚡ Bolt: [performance improvement] Memoize WebSocket list items to prevent re-renders

[primoscope]

💡 What: Extracted the inline LogItem and DownloadItem components from LogPanel.tsx and ProgressPanel.tsx respectively, and wrapped them in React.memo(). Also hoisted pure helper functions like getLogColor, formatSpeed, formatETA, and getStatusColor outside of the component bodies. Added inline comments to document the optimizations. Added a critical learning to .jules/bolt.md.

🎯 Why: When building lists that receive high-frequency updates via WebSocket, rendering lists inline with helper functions defined inside the component body creates a massive re-render bottleneck. Because a single WebSocket update updates the entire array state, React was re-rendering all list items instead of just the changed ones, and re-allocating helper functions on every single render cycle.

📊 Impact: Prevents unnecessary re-renders of the entire download/log list when high-frequency WebSocket updates arrive. Only the specific items that change (or new items that are appended) will trigger a render. This greatly reduces CPU overhead and DOM updates on the frontend.

🔬 Measurement: To verify, you can use React Developer Tools Profiler. Start a mock server sending WebSocket events every second and observe the ProgressPanel and LogPanel components. You will see that DownloadItem and LogItem components do not re-render unless their specific download or log props change.

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PR created automatically by Jules for task 12413171551721026586 started by @dzp5103

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