feat: Improve expert diversity and description reliability

- Add random seed and diversity hints to expert generation prompt
- Explicitly avoid common professions (醫生、工程師、教師、律師等)
- Change description generation from batch to one-by-one for reliability
- Increase default temperature from 0.7 to 0.95 for more creative output
- Add description_progress SSE event for real-time feedback

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/App.tsx

@@ -33,7 +33,7 @@ function App() {
 
   // Transformation Agent settings
   const [transformModel, setTransformModel] = useState<string>('');
-  const [transformTemperature, setTransformTemperature] = useState<number>(0.7);
+  const [transformTemperature, setTransformTemperature] = useState<number>(0.95);
   const [expertConfig, setExpertConfig] = useState<{
     expert_count: number;
     keywords_per_expert: number;