useSettingFocus rides the useFocusParam rail with a new `setting` kind: a
palette result navigates to /settings/<tab>?focus=setting:<id>, and the target
card scrolls into view and flashes a token-based highlight for ~2s. Wires the
headline Security (2FA card + admin require-2FA policy, now mounted) and
Notifications (email/SMTP, channels, severity, categories, quiet hours) cards.
Adds scripts/check-settings-index.mjs (dependency-free) to the lint step so
every settings tab must carry at least one index entry — a new tab can't ship
invisible to search.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
