feat(dashboard): Enhanced chat, spec management, and Claude integration

Backend:
- spec.py: New AtomizerSpec REST API endpoints
- spec_manager.py: SpecManager service for unified config
- interview_engine.py: Study creation interview logic
- claude.py: Enhanced Claude API with context
- optimization.py: Extended optimization endpoints
- context_builder.py, session_manager.py: Improved services

Frontend:
- Chat components: Enhanced message rendering, tool call cards
- Hooks: useClaudeCode, useSpecWebSocket, improved useChat
- Pages: Updated Dashboard, Analysis, Insights, Setup, Home
- Components: ParallelCoordinatesPlot, ParetoPlot improvements
- App.tsx: Route updates for canvas/studio

Infrastructure:
- vite.config.ts: Build configuration updates
- start/stop-dashboard.bat: Script improvements

atomizer-dashboard/frontend/src/components/chat/ChatMessage.tsx

@@ -5,7 +5,7 @@ import { ToolCallCard, ToolCall } from './ToolCallCard';
 
 export interface Message {
   id: string;
-  role: 'user' | 'assistant';
+  role: 'user' | 'assistant' | 'system';
   content: string;
   timestamp: Date;
   isStreaming?: boolean;
@@ -18,6 +18,18 @@ interface ChatMessageProps {
 
 export const ChatMessage: React.FC<ChatMessageProps> = ({ message }) => {
   const isAssistant = message.role === 'assistant';
+  const isSystem = message.role === 'system';
+
+  // System messages are displayed centered with special styling
+  if (isSystem) {
+    return (
+      <div className="flex justify-center my-2">
+        <div className="px-3 py-1 bg-dark-700/50 rounded-full text-xs text-dark-400 border border-dark-600">
+          {message.content}
+        </div>
+      </div>
+    );
+  }
 
   return (
     <div