resolve_language(Some("EN"), false) was passed through unchanged instead of
being normalized to lowercase "en" - the English-only-model guard only fired
when the requested language *differed* from English, not when it matched with
different casing. Also fixes cargo fmt drift in mod.rs/npu.rs left over from
the M4.2 worktree (stopped mid-verification per session instruction before
running fmt).
iamdoubz
40709b257d