139Design a large enterprise React application with micro-frontends, permissions, and deployment strategies

Design the frontend architecture for a large enterprise product (think an HR, finance or CRM suite) built by 15 teams:

• dozens of modules (Employees, Payroll, Expenses, Reports, Admin) with hundreds of screens;
• fine-grained permissions: what a user can see and do depends on roles, organisation unit and record ownership, and admins can change them at any time;
• frequent, safe releases with feature flags, gradual rollouts and quick rollback;
• consistent UX and accessibility across all teams; multi-tenant (each customer company has its own configuration and branding).

Cover the code organisation (monorepo vs micro-frontends), the permission model on the client, routing and data access, the design system, and the build and deployment pipeline.