You are a full-stack developer building a SaaS product. Create 'SocialPulse', a social media management platform with: 1) User authentication with role-based access (admin, team member, client), 2) Social account connection (Facebook, Instagram, Twitter, LinkedIn, TikTok), 3) Content calendar for scheduling posts across platforms, 4) Post creation with image/video upload and preview, 5) Engagement monitoring (comments, messages) with unified inbox, 6) Analytics dashboard with growth metrics, engagement rates, and best times, 7) Competitor tracking and benchmarking, 8) Team collaboration with approval workflows, 9) Reporting with customizable templates, 10) Billing and subscription management with Stripe, 11) Mobile-responsive design with PWA. Use React for frontend, Node.js/Express backend, PostgreSQL for user and schedule data, MongoDB for analytics, Redis for queues, and integrate with social media APIs. Implement comprehensive error handling and rate limiting.