feat: Add Expert Transformation Agent with multi-expert perspective system

- Backend: Add expert transformation router with 3-step SSE pipeline
  - Step 0: Generate diverse expert team (random domains)
  - Step 1: Each expert generates keywords for attributes
  - Step 2: Batch generate descriptions for expert keywords
- Backend: Add simplified prompts for reliable JSON output
- Frontend: Add TransformationPanel with React Flow visualization
- Frontend: Add TransformationInputPanel for expert configuration
  - Expert count (2-8), keywords per expert (1-3)
  - Custom expert domains support
- Frontend: Add expert keyword nodes with expert badges
- Frontend: Improve description card layout (wider cards, more spacing)
- Frontend: Add fallback for missing descriptions with visual indicators

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

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

frontend/src/components/transformation/index.ts

@@ -0,0 +1,29 @@
+import { KeywordNode } from './nodes/KeywordNode';
+import { ExpertKeywordNode } from './nodes/ExpertKeywordNode';
+import { DescriptionNode } from './nodes/DescriptionNode';
+import { CategoryNode } from './nodes/CategoryNode';
+import { OriginalAttributeNode } from './nodes/OriginalAttributeNode';
+import { DividerNode } from './nodes/DividerNode';
+import { QueryNode } from '../dag/nodes/QueryNode';
+
+export const transformationNodeTypes = {
+  query: QueryNode,
+  category: CategoryNode,
+  keyword: KeywordNode,
+  expertKeyword: ExpertKeywordNode,
+  description: DescriptionNode,
+  originalAttribute: OriginalAttributeNode,
+  divider: DividerNode,
+};
+
+export {
+  KeywordNode,
+  ExpertKeywordNode,
+  DescriptionNode,
+  CategoryNode,
+  OriginalAttributeNode,
+  DividerNode
+};
+export { useTransformationLayout } from './useTransformationLayout';
+export { useExpertTransformationLayout } from './useExpertTransformationLayout';
+export { ExpertConfigPanel } from './ExpertConfigPanel';