Redirects were built relative to `request.url`, which behind a reverse proxy
resolves to the container-internal address. Verification succeeded but the
browser was sent to localhost:3000, so users saw a connection error instead of
the "email verified" confirmation.
Add getPublicOrigin() (NEXTAUTH_URL, then NEXT_PUBLIC_APP_URL, falling back to
the request origin for local development) and use it for every verify-email
redirect. The legacy GET redirect in the watch session route had the same
defect and is fixed alongside it.
yusufipk