- new_install_privacy_defaults and the scheduler's CheckDomainTasks
looked unused in test builds, whose callers are
cfg(not(feature = "test_mode")); allow dead_code there only.
- live.rs: fetch_update is deprecated as of Rust 1.99; try_update is the
same call under its new name (present in CI's 1.98 too).
- Two test servers that are never mutated lose their `mut`.
The one warning left is in vendored hickory-resolver (an `h3` variable
gated on `__tls` instead of `__h3`). VENDORED.md keeps that copy
unchanged, so it stays.