fix: resolve onboarding session not found warnings and frontend build OOM

- Use canonical Clerk user id (clerk_user_id) across all onboarding entrypoints to ensure consistent OnboardingSession.user_id lookup
- Fix API key persistence in api_key_manager.py to use correct APIKey model columns (session_id, provider, key)
- Increase Node heap for frontend build to 8GB and add build:nomap script to disable sourcemaps and reduce memory usage
- Update onboarding endpoints (endpoints_core.py, onboarding_control_service.py, step_management_service.py) to prefer clerk_user_id over id
- Fix frontend workflowStore.ts TypeScript error by returning WorkflowError instance
- Add website_automation_service.py for onboarding automation

frontend/src/stores/workflowStore.ts

@@ -54,12 +54,12 @@ const toWorkflowError = (error: unknown, fallbackMessage: string): WorkflowError
   if (error instanceof WorkflowError) return error;
 
   const message = error instanceof Error ? error.message : fallbackMessage;
-  return {
+  return new WorkflowError({
     code: 'WORKFLOW_ERROR',
     message,
     timestamp: new Date(),
     recoverable: false,
-  };
+  });
 };
 
 const computeProgressAndNavigation = (workflow: DailyWorkflow): { progress: WorkflowProgress; navigation: NavigationState } => {