Reviewed-on: graham/towerops-web#181
Add missing dark: variant classes to: - consent_prompt, check_live/form_component: modal overlays - error pages (404, 500): body background - marketing_layouts: page background - home page: pricing card, CTA button, feature card - totp_enrollment: QR container - admin audit_live/monitoring_live: badge colors, event borders - alert_live: acknowledged-by text - dashboard_live: severity color fallback - device_live (index, show, form): status text, spinners - settings_live: checkbox borders - trace_live: status colors, labels, table headers
wire time_format into scope, add settings UI selector, change defaults to 24h, and replace all user-facing Calendar.strftime calls with centralized TimeHelpers using the user's timezone and time format.
