⚡ Bolt: Optimize ChatMessageItem re-renders with React.memo

[Psyborgs-git]

💡 What: The ChatMessageItem component in @orch/web-ui was wrapped with React.memo and a custom equality function was added to compare specific props (msg.id, msg.content, msg.toolCalls, msg.toolResults, disabledActions, isGrouped).

🎯 Why: When a new chunk arrives during an AI chat response, the entire sessions array is replaced, which triggers a re-render of ChatMessagesList. Since ChatMessageItem is a heavy component (rendering markdown, tool logs, syntax highlighting), re-rendering every previous message in the chat history on every chunk caused severe UI lag and jank as the chat history grew. React.memo ensures that only the active streaming message (whose content is changing) and actually modified messages are re-rendered.

📊 Impact: Reduces CPU usage and unnecessary re-renders in the ChatView by ~O(N) (where N is the number of previous messages in the chat session). This will result in significantly smoother scrolling and streaming experience in long conversation contexts.

🔬 Measurement:

1. Open the Chat UI and create a long conversation with multiple turns.
2. Ask the AI agent a long question that streams a response.
3. Observe React Profiler: ChatMessageItem components for prior messages will now show "Did not render" instead of re-rendering on every token chunk.

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PR created automatically by Jules for task 12431176547593783766 started by @Psyborgs-git

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