warn_if_editable_deps_stale() -> NonePrint the stale-dependency warning to stderr for non-TUI launches.
Skips silently when there are no violations or the exact mismatch was
muted for this checkout. This is strictly best-effort: any unexpected
failure degrades to a debug log and never raises. The warning goes to
stderr so it never contaminates the stdout these launches produce for a
caller to consume (a piped -n answer, a subcommand's output).