Summary
This commit addresses two critical issues affecting the real-time chat experience in the Playground:
1. Optimized re-rendering of reasoning content
• Added `reasoningContent` to the comparison function of `OptimizedMessageContent` (`web/src/components/playground/OptimizedComponents.js`).
• Ensures the component re-renders while reasoning text streams, resolving the bug where only the first characters (“好,”) were shown until the stream finished.
2. Defensive checks for SSE message updates
• Added early-return guards in `streamMessageUpdate` (`web/src/hooks/useApiRequest.js`).
• Skips updates when `lastMessage` is undefined or the last message isn’t from the assistant, preventing `TypeError: Cannot read properties of undefined (reading 'status')` during rapid SSE responses.
Impact
• Real-time reasoning content now appears progressively, enhancing user feedback.
• Eliminates runtime crashes caused by undefined message references, improving overall stability.
