Server-rendered user modules can currently observe a partially populated browser global when the runtime provides one. That violates Next.js SSR semantics, where server code must see browser globals as absent, and it breaks common typeof window guards during module evaluation.
Add a shared server globals bootstrap that removes window and document before user modules load, preserves the existing AsyncLocalStorage edge-runtime global, and import it ahead of generated App and Pages Router user imports. Cover the runtime behavior and generated import order with focused regression tests.
Nathan Nguyen